<XBRL>
<?xml version="1.0" encoding="us-ascii"?>
<!-- Created by Merrill Corporation -->
<!-- Generated by Fujitsu Interstage XWand B0160 -->
<linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:amg="http://www.amg.com/20111231" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
  <roleRef roleURI="http://www.amg.com/role/StatementOfStockholdersEquity" xlink:type="simple" xlink:href="amg-20111231.xsd#StatementOfStockholdersEquity" />
  <roleRef roleURI="http://www.amg.com/role/BalanceSheet" xlink:type="simple" xlink:href="amg-20111231.xsd#BalanceSheet" />
  <roleRef roleURI="http://www.amg.com/role/CashFlows" xlink:type="simple" xlink:href="amg-20111231.xsd#CashFlows" />
  <roleRef roleURI="http://www.amg.com/role/StatementOfIncome" xlink:type="simple" xlink:href="amg-20111231.xsd#StatementOfIncome" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureCommitmentsAndContingenciesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureCommitmentsAndContingenciesDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureVariableInterestEntitiesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureVariableInterestEntitiesDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureGoodwillAndAcquiredClientRelationshipsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureGoodwillAndAcquiredClientRelationshipsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureSegmentInformationDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureSegmentInformationDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureConvertibleSecuritiesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureConvertibleSecuritiesDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureJuniorConvertibleTrustPreferredSecuritiesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureJuniorConvertibleTrustPreferredSecuritiesDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureDerivativeFinancialInstrumentsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureDerivativeFinancialInstrumentsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureDerivativeFinancialInstrumentsDetails2" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureDerivativeFinancialInstrumentsDetails2" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureDerivativeFinancialInstrumentsDetails3" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureDerivativeFinancialInstrumentsDetails3" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureIncomeTaxesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureIncomeTaxesDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureRelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureRelatedPartyTransactionsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureFairValueMeasurementsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureFairValueMeasurementsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureFairValueMeasurementsDetails2" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureFairValueMeasurementsDetails2" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureFairValueMeasurementsDetails3" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureFairValueMeasurementsDetails3" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureGoodwillAndAcquiredClientRelationshipsDetails2" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureGoodwillAndAcquiredClientRelationshipsDetails2" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureForwardEquitySaleAgreementsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureForwardEquitySaleAgreementsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureInvestmentsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureInvestmentsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureEarningsPerShareDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureEarningsPerShareDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureBusinessAndSummaryOfSignificantAccountingPoliciesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureBusinessAndSummaryOfSignificantAccountingPoliciesDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureFixedAssetsAndLeaseCommitmentsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureFixedAssetsAndLeaseCommitmentsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureStockholdersEquityDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureStockholdersEquityDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureStockholdersEquityDetails2" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureStockholdersEquityDetails2" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureStockholdersEquityDetails3" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureStockholdersEquityDetails3" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureFinancialInstrumentsAndRiskManagementDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureFinancialInstrumentsAndRiskManagementDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureValuationAndQualifyingAccountsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureValuationAndQualifyingAccountsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureBusinessCombinationsDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureBusinessCombinationsDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureEquityInvestmentsInAffiliatesDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureEquityInvestmentsInAffiliatesDetails" />
  <roleRef roleURI="http://www.amg.com/role/StatementOfComprehensiveIncome" xlink:type="simple" xlink:href="amg-20111231.xsd#StatementOfComprehensiveIncome" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureComprehensiveIncomeDetails2" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureComprehensiveIncomeDetails2" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureSeniorBankDebtDetails" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureSeniorBankDebtDetails" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureInvestmentsDetails2" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureInvestmentsDetails2" />
  <roleRef roleURI="http://www.amg.com/role/DisclosureInvestmentsDetails3" xlink:type="simple" xlink:href="amg-20111231.xsd#DisclosureInvestmentsDetails3" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/StatementOfStockholdersEquity">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" use="optional" order="10.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: StatementTable to StatementEquityComponentsAxis" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis_2" xlink:title="StatementEquityComponentsAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain_2" xlink:title="EquityComponentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementEquityComponentsAxis_2" xlink:to="EquityComponentDomain_2" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EquityComponentDomain to NoncontrollingInterestMember" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ParentCompanyMember" xlink:label="ParentCompanyMember" xlink:title="ParentCompanyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="ParentCompanyMember" xlink:title="definition: EquityComponentDomain to ParentCompanyMember" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentCompanyMember" xlink:to="CommonStockMember" xlink:title="definition: ParentCompanyMember to CommonStockMember" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="AdditionalPaidInCapitalMember" xlink:title="AdditionalPaidInCapitalMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentCompanyMember" xlink:to="AdditionalPaidInCapitalMember" xlink:title="definition: ParentCompanyMember to AdditionalPaidInCapitalMember" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentCompanyMember" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: ParentCompanyMember to AccumulatedOtherComprehensiveIncomeMember" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="RetainedEarningsMember" xlink:title="RetainedEarningsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentCompanyMember" xlink:to="RetainedEarningsMember" xlink:title="definition: ParentCompanyMember to RetainedEarningsMember" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockMember" xlink:label="TreasuryStockMember" xlink:title="TreasuryStockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ParentCompanyMember" xlink:to="TreasuryStockMember" xlink:title="definition: ParentCompanyMember to TreasuryStockMember" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_NoncontrollingInterestInPartnershipsMember" xlink:label="NoncontrollingInterestInPartnershipsMember" xlink:title="NoncontrollingInterestInPartnershipsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="NoncontrollingInterestInPartnershipsMember" xlink:title="definition: EquityComponentDomain to NoncontrollingInterestInPartnershipsMember" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="IncreaseDecreaseInStockholdersEquityRollForward" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncreaseDecreaseInStockholdersEquityRollForward" xlink:title="definition: StatementLineItems to IncreaseDecreaseInStockholdersEquityRollForward" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:label="StockIssuedDuringPeriodValueShareBasedCompensation" xlink:title="StockIssuedDuringPeriodValueShareBasedCompensation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueShareBasedCompensation" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueShareBasedCompensation" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:label="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:title="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:label="AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:title="AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ChangesInAffiliateEquity" xlink:label="ChangesInAffiliateEquity" xlink:title="ChangesInAffiliateEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="ChangesInAffiliateEquity" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to ChangesInAffiliateEquity" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedDuringPeriodValueSettlementOfForwardEquitySaleAgreements" xlink:label="StockIssuedDuringPeriodValueSettlementOfForwardEquitySaleAgreements" xlink:title="StockIssuedDuringPeriodValueSettlementOfForwardEquitySaleAgreements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueSettlementOfForwardEquitySaleAgreements" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueSettlementOfForwardEquitySaleAgreements" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:label="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:title="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueConversionOfConvertibleSecurities" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:label="MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:title="MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" use="optional" order="80.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentsInAffiliates" xlink:label="InvestmentsInAffiliates" xlink:title="InvestmentsInAffiliates" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="InvestmentsInAffiliates" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to InvestmentsInAffiliates" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_MinorityInterestInPartnershipsOtherChanges" xlink:label="MinorityInterestInPartnershipsOtherChanges" xlink:title="MinorityInterestInPartnershipsOtherChanges" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="MinorityInterestInPartnershipsOtherChanges" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to MinorityInterestInPartnershipsOtherChanges" use="optional" order="110.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="ProfitLoss" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to ProfitLoss" use="optional" order="120.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" use="optional" order="130.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" use="optional" order="140.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityPeriodIncreaseDecrease" xlink:label="StockholdersEquityPeriodIncreaseDecrease" xlink:title="StockholdersEquityPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockholdersEquityPeriodIncreaseDecrease" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockholdersEquityPeriodIncreaseDecrease" use="optional" order="150.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IssuanceOfJuniorConvertibleTrustPreferredSecurities" xlink:label="IssuanceOfJuniorConvertibleTrustPreferredSecurities" xlink:title="IssuanceOfJuniorConvertibleTrustPreferredSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="IssuanceOfJuniorConvertibleTrustPreferredSecurities" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to IssuanceOfJuniorConvertibleTrustPreferredSecurities" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestDecreaseFromRedemptions" xlink:label="MinorityInterestDecreaseFromRedemptions" xlink:title="MinorityInterestDecreaseFromRedemptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="MinorityInterestDecreaseFromRedemptions" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to MinorityInterestDecreaseFromRedemptions" use="optional" order="8010.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedDuringPeriodValueSettlementOfCallSpreadOptionAgreements" xlink:label="StockIssuedDuringPeriodValueSettlementOfCallSpreadOptionAgreements" xlink:title="StockIssuedDuringPeriodValueSettlementOfCallSpreadOptionAgreements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueSettlementOfCallSpreadOptionAgreements" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueSettlementOfCallSpreadOptionAgreements" use="optional" order="8020.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CostOfCallSpreadOptionAgreements" xlink:label="CostOfCallSpreadOptionAgreements" xlink:title="CostOfCallSpreadOptionAgreements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="CostOfCallSpreadOptionAgreements" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to CostOfCallSpreadOptionAgreements" use="optional" order="8030.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IssuanceOfSeniorConvertibleSecurities" xlink:label="IssuanceOfSeniorConvertibleSecurities" xlink:title="IssuanceOfSeniorConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="IssuanceOfSeniorConvertibleSecurities" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to IssuanceOfSeniorConvertibleSecurities" use="optional" order="8040.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedDuringPeriodValueSettlementOfMandatoryConvertibleSecurities" xlink:label="StockIssuedDuringPeriodValueSettlementOfMandatoryConvertibleSecurities" xlink:title="StockIssuedDuringPeriodValueSettlementOfMandatoryConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueSettlementOfMandatoryConvertibleSecurities" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueSettlementOfMandatoryConvertibleSecurities" use="optional" order="8050.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedDuringPeriodValueSettlementOfFloatingRateSeniorConvertibleSecurities" xlink:label="StockIssuedDuringPeriodValueSettlementOfFloatingRateSeniorConvertibleSecurities" xlink:title="StockIssuedDuringPeriodValueSettlementOfFloatingRateSeniorConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="StockIssuedDuringPeriodValueSettlementOfFloatingRateSeniorConvertibleSecurities" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to StockIssuedDuringPeriodValueSettlementOfFloatingRateSeniorConvertibleSecurities" use="optional" order="8060.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromConversionOfForwardEquitySaleAgreement" xlink:label="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromConversionOfForwardEquitySaleAgreement" xlink:title="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromConversionOfForwardEquitySaleAgreement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="AdjustmentsToAdditionalPaidInCapitalTaxEffectFromConversionOfForwardEquitySaleAgreement" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to AdjustmentsToAdditionalPaidInCapitalTaxEffectFromConversionOfForwardEquitySaleAgreement" use="optional" order="8070.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod" xlink:label="TreasuryStockValueAcquiredCostMethod" xlink:title="TreasuryStockValueAcquiredCostMethod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="TreasuryStockValueAcquiredCostMethod" xlink:title="definition: IncreaseDecreaseInStockholdersEquityRollForward to TreasuryStockValueAcquiredCostMethod" use="optional" order="100.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/StatementOfIncome">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="10.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementScenarioAxis" xlink:title="definition: StatementTable to StatementScenarioAxis" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetManagementFees" xlink:label="AssetManagementFees" xlink:title="AssetManagementFees" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetManagementFees" xlink:title="definition: StatementLineItems to AssetManagementFees" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="OperatingExpensesAbstract" xlink:title="OperatingExpensesAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingExpensesAbstract" xlink:title="definition: StatementLineItems to OperatingExpensesAbstract" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="LaborAndRelatedExpense" xlink:title="LaborAndRelatedExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="LaborAndRelatedExpense" xlink:title="definition: OperatingExpensesAbstract to LaborAndRelatedExpense" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="SellingGeneralAndAdministrativeExpense" xlink:title="SellingGeneralAndAdministrativeExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="SellingGeneralAndAdministrativeExpense" xlink:title="definition: OperatingExpensesAbstract to SellingGeneralAndAdministrativeExpense" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="AmortizationOfIntangibleAssets" xlink:title="definition: OperatingExpensesAbstract to AmortizationOfIntangibleAssets" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DepreciationAndOtherAmortization" xlink:label="DepreciationAndOtherAmortization" xlink:title="DepreciationAndOtherAmortization" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="DepreciationAndOtherAmortization" xlink:title="definition: OperatingExpensesAbstract to DepreciationAndOtherAmortization" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherCostAndExpenseOperating" xlink:label="OtherCostAndExpenseOperating" xlink:title="OtherCostAndExpenseOperating" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="OtherCostAndExpenseOperating" xlink:title="definition: OperatingExpensesAbstract to OtherCostAndExpenseOperating" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="OperatingExpenses" xlink:title="OperatingExpenses" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="OperatingExpenses" xlink:title="definition: OperatingExpensesAbstract to OperatingExpenses" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OperatingIncomeLoss" xlink:title="definition: StatementLineItems to OperatingIncomeLoss" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="NonoperatingIncomeExpenseAbstract" xlink:title="NonoperatingIncomeExpenseAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NonoperatingIncomeExpenseAbstract" xlink:title="definition: StatementLineItems to NonoperatingIncomeExpenseAbstract" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentAndOtherIncomeLoss" xlink:label="InvestmentAndOtherIncomeLoss" xlink:title="InvestmentAndOtherIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="InvestmentAndOtherIncomeLoss" xlink:title="definition: NonoperatingIncomeExpenseAbstract to InvestmentAndOtherIncomeLoss" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: NonoperatingIncomeExpenseAbstract to IncomeLossFromEquityMethodInvestments" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentIncomeLossFromInvestmentsInPartnerships" xlink:label="InvestmentIncomeLossFromInvestmentsInPartnerships" xlink:title="InvestmentIncomeLossFromInvestmentsInPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="InvestmentIncomeLossFromInvestmentsInPartnerships" xlink:title="definition: NonoperatingIncomeExpenseAbstract to InvestmentIncomeLossFromInvestmentsInPartnerships" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestExpense" xlink:label="InterestExpense" xlink:title="InterestExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="InterestExpense" xlink:title="definition: NonoperatingIncomeExpenseAbstract to InterestExpense" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ImputedInterest" xlink:label="ImputedInterest" xlink:title="ImputedInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="ImputedInterest" xlink:title="definition: NonoperatingIncomeExpenseAbstract to ImputedInterest" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="NonoperatingIncomeExpense" xlink:title="NonoperatingIncomeExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="NonoperatingIncomeExpense" xlink:title="definition: NonoperatingIncomeExpenseAbstract to NonoperatingIncomeExpense" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: StatementLineItems to IncomeTaxExpenseBenefit" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ProfitLoss" xlink:title="definition: StatementLineItems to ProfitLoss" use="optional" order="80.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:label="MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:title="MinorityInterestInNetIncomeLossOtherMinorityInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:title="definition: StatementLineItems to MinorityInterestInNetIncomeLossOtherMinorityInterests" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestInNetIncomeLossOperatingPartnerships" xlink:label="MinorityInterestInNetIncomeLossOperatingPartnerships" xlink:title="MinorityInterestInNetIncomeLossOperatingPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="MinorityInterestInNetIncomeLossOperatingPartnerships" xlink:title="definition: StatementLineItems to MinorityInterestInNetIncomeLossOperatingPartnerships" use="optional" order="100.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetIncomeLoss" xlink:title="definition: StatementLineItems to NetIncomeLoss" use="optional" order="110.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="EarningsPerShareBasic" xlink:title="EarningsPerShareBasic" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EarningsPerShareBasic" xlink:title="definition: StatementLineItems to EarningsPerShareBasic" use="optional" order="120.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="EarningsPerShareDiluted" xlink:title="EarningsPerShareDiluted" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EarningsPerShareDiluted" xlink:title="definition: StatementLineItems to EarningsPerShareDiluted" use="optional" order="130.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="WeightedAverageNumberOfSharesOutstandingBasic" xlink:title="WeightedAverageNumberOfSharesOutstandingBasic" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="WeightedAverageNumberOfSharesOutstandingBasic" xlink:title="definition: StatementLineItems to WeightedAverageNumberOfSharesOutstandingBasic" use="optional" order="140.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="WeightedAverageNumberOfDilutedSharesOutstanding" xlink:title="WeightedAverageNumberOfDilutedSharesOutstanding" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="WeightedAverageNumberOfDilutedSharesOutstanding" xlink:title="definition: StatementLineItems to WeightedAverageNumberOfDilutedSharesOutstanding" use="optional" order="150.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncomeLossFromContinuingOperationsAfterIncomeLossFromEquityMethodInvestmentsButBeforeIncomeTaxesAndMinorityInterest" xlink:label="IncomeLossFromContinuingOperationsAfterIncomeLossFromEquityMethodInvestmentsButBeforeIncomeTaxesAndMinorityInterest" xlink:title="IncomeLossFromContinuingOperationsAfterIncomeLossFromEquityMethodInvestmentsButBeforeIncomeTaxesAndMinorityInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IncomeLossFromContinuingOperationsAfterIncomeLossFromEquityMethodInvestmentsButBeforeIncomeTaxesAndMinorityInterest" xlink:title="definition: StatementLineItems to IncomeLossFromContinuingOperationsAfterIncomeLossFromEquityMethodInvestmentsButBeforeIncomeTaxesAndMinorityInterest" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IntangibleRelatedDeferredIncomeTaxExpenseBenefit" xlink:label="IntangibleRelatedDeferredIncomeTaxExpenseBenefit" xlink:title="IntangibleRelatedDeferredIncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="IntangibleRelatedDeferredIncomeTaxExpenseBenefit" xlink:title="definition: StatementLineItems to IntangibleRelatedDeferredIncomeTaxExpenseBenefit" use="optional" order="8010.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredOtherTaxExpenseBenefit" xlink:label="DeferredOtherTaxExpenseBenefit" xlink:title="DeferredOtherTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="DeferredOtherTaxExpenseBenefit" xlink:title="definition: StatementLineItems to DeferredOtherTaxExpenseBenefit" use="optional" order="8020.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/BalanceSheet">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="10.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementScenarioAxis" xlink:title="definition: StatementTable to StatementScenarioAxis" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain_2" xlink:title="ScenarioUnspecifiedDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain_2" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" use="optional" priority="1" order="20.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsAbstract" xlink:label="AssetsAbstract" xlink:title="AssetsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AssetsAbstract" xlink:title="definition: StatementLineItems to AssetsAbstract" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsCurrentAbstract" xlink:label="AssetsCurrentAbstract" xlink:title="AssetsCurrentAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="AssetsCurrentAbstract" xlink:title="definition: AssetsAbstract to AssetsCurrentAbstract" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsCurrentAbstract" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: AssetsCurrentAbstract to CashAndCashEquivalentsAtCarryingValue" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="AccountsReceivableNetCurrent" xlink:title="AccountsReceivableNetCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsCurrentAbstract" xlink:to="AccountsReceivableNetCurrent" xlink:title="definition: AssetsCurrentAbstract to AccountsReceivableNetCurrent" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MarketableSecuritiesCurrent" xlink:label="MarketableSecuritiesCurrent" xlink:title="MarketableSecuritiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsCurrentAbstract" xlink:to="MarketableSecuritiesCurrent" xlink:title="definition: AssetsCurrentAbstract to MarketableSecuritiesCurrent" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_UnsettledFundShareReceivables" xlink:label="UnsettledFundShareReceivables" xlink:title="UnsettledFundShareReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsCurrentAbstract" xlink:to="UnsettledFundShareReceivables" xlink:title="definition: AssetsCurrentAbstract to UnsettledFundShareReceivables" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="AssetsCurrent" xlink:title="AssetsCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsCurrentAbstract" xlink:to="AssetsCurrent" xlink:title="definition: AssetsCurrentAbstract to AssetsCurrent" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="PrepaidExpenseAndOtherAssetsCurrent" xlink:title="PrepaidExpenseAndOtherAssetsCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsCurrentAbstract" xlink:to="PrepaidExpenseAndOtherAssetsCurrent" xlink:title="definition: AssetsCurrentAbstract to PrepaidExpenseAndOtherAssetsCurrent" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: AssetsAbstract to PropertyPlantAndEquipmentNet" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:title="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:title="definition: AssetsAbstract to InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="IntangibleAssetsNetExcludingGoodwill" xlink:title="IntangibleAssetsNetExcludingGoodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="IntangibleAssetsNetExcludingGoodwill" xlink:title="definition: AssetsAbstract to IntangibleAssetsNetExcludingGoodwill" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="Goodwill" xlink:title="definition: AssetsAbstract to Goodwill" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherAssetsNoncurrent" xlink:label="OtherAssetsNoncurrent" xlink:title="OtherAssetsNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="OtherAssetsNoncurrent" xlink:title="definition: AssetsAbstract to OtherAssetsNoncurrent" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Assets" xlink:label="Assets" xlink:title="Assets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsAbstract" xlink:to="Assets" xlink:title="definition: AssetsAbstract to Assets" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="LiabilitiesAndStockholdersEquityAbstract" xlink:title="LiabilitiesAndStockholdersEquityAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="LiabilitiesAndStockholdersEquityAbstract" xlink:title="definition: StatementLineItems to LiabilitiesAndStockholdersEquityAbstract" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesCurrentAbstract" xlink:label="LiabilitiesCurrentAbstract" xlink:title="LiabilitiesCurrentAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="LiabilitiesCurrentAbstract" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to LiabilitiesCurrentAbstract" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="AccountsPayableAndAccruedLiabilitiesCurrent" xlink:title="AccountsPayableAndAccruedLiabilitiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesCurrentAbstract" xlink:to="AccountsPayableAndAccruedLiabilitiesCurrent" xlink:title="definition: LiabilitiesCurrentAbstract to AccountsPayableAndAccruedLiabilitiesCurrent" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_UnsettledFundSharePayables" xlink:label="UnsettledFundSharePayables" xlink:title="UnsettledFundSharePayables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesCurrentAbstract" xlink:to="UnsettledFundSharePayables" xlink:title="definition: LiabilitiesCurrentAbstract to UnsettledFundSharePayables" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:label="DueToRelatedPartiesCurrent" xlink:title="DueToRelatedPartiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesCurrentAbstract" xlink:to="DueToRelatedPartiesCurrent" xlink:title="definition: LiabilitiesCurrentAbstract to DueToRelatedPartiesCurrent" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="LiabilitiesCurrent" xlink:title="LiabilitiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesCurrentAbstract" xlink:to="LiabilitiesCurrent" xlink:title="definition: LiabilitiesCurrentAbstract to LiabilitiesCurrent" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LongTermLineOfCredit" xlink:label="LongTermLineOfCredit" xlink:title="LongTermLineOfCredit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="LongTermLineOfCredit" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to LongTermLineOfCredit" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SeniorConvertibleDebtNoncurrent" xlink:label="SeniorConvertibleDebtNoncurrent" xlink:title="SeniorConvertibleDebtNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="SeniorConvertibleDebtNoncurrent" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to SeniorConvertibleDebtNoncurrent" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredDebtNoncurrent" xlink:label="JuniorConvertibleTrustPreferredDebtNoncurrent" xlink:title="JuniorConvertibleTrustPreferredDebtNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="JuniorConvertibleTrustPreferredDebtNoncurrent" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to JuniorConvertibleTrustPreferredDebtNoncurrent" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredTaxLiabilitiesNoncurrent" xlink:label="DeferredTaxLiabilitiesNoncurrent" xlink:title="DeferredTaxLiabilitiesNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="DeferredTaxLiabilitiesNoncurrent" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to DeferredTaxLiabilitiesNoncurrent" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="OtherLiabilitiesNoncurrent" xlink:title="OtherLiabilitiesNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="OtherLiabilitiesNoncurrent" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to OtherLiabilitiesNoncurrent" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Liabilities" xlink:label="Liabilities" xlink:title="Liabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="Liabilities" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to Liabilities" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockValue" xlink:label="CommonStockValue" xlink:title="CommonStockValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="CommonStockValue" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to CommonStockValue" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="AdditionalPaidInCapitalCommonStock" xlink:title="AdditionalPaidInCapitalCommonStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="AdditionalPaidInCapitalCommonStock" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to AdditionalPaidInCapitalCommonStock" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to AccumulatedOtherComprehensiveIncomeLossNetOfTax" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="RetainedEarningsAccumulatedDeficit" xlink:title="RetainedEarningsAccumulatedDeficit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="RetainedEarningsAccumulatedDeficit" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to RetainedEarningsAccumulatedDeficit" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="TreasuryStockValue" xlink:title="TreasuryStockValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="TreasuryStockValue" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to TreasuryStockValue" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="StockholdersEquity" xlink:title="StockholdersEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="StockholdersEquity" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to StockholdersEquity" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherMinorityInterests" xlink:label="OtherMinorityInterests" xlink:title="OtherMinorityInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="OtherMinorityInterests" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to OtherMinorityInterests" use="optional" order="80.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestInOperatingPartnerships" xlink:label="MinorityInterestInOperatingPartnerships" xlink:title="MinorityInterestInOperatingPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="MinorityInterestInOperatingPartnerships" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to MinorityInterestInOperatingPartnerships" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityBeforeTreasuryStock" xlink:label="StockholdersEquityBeforeTreasuryStock" xlink:title="StockholdersEquityBeforeTreasuryStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="StockholdersEquityBeforeTreasuryStock" xlink:title="definition: StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract to StockholdersEquityBeforeTreasuryStock" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="LiabilitiesAndStockholdersEquity" xlink:title="LiabilitiesAndStockholdersEquity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="LiabilitiesAndStockholdersEquity" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to LiabilitiesAndStockholdersEquity" use="optional" order="100.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount" xlink:label="RedeemableNoncontrollingInterestEquityCarryingAmount" xlink:title="RedeemableNoncontrollingInterestEquityCarryingAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesAndStockholdersEquityAbstract" xlink:to="RedeemableNoncontrollingInterestEquityCarryingAmount" xlink:title="definition: LiabilitiesAndStockholdersEquityAbstract to RedeemableNoncontrollingInterestEquityCarryingAmount" use="optional" order="80.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/CashFlows">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" use="optional" order="10.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementScenarioAxis" xlink:title="definition: StatementTable to StatementScenarioAxis" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:label="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:title="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:title="definition: StatementLineItems to NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="ProfitLoss" xlink:title="definition: NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract to ProfitLoss" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:title="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:title="definition: NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract to AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="AmortizationOfIntangibleAssets" xlink:title="AmortizationOfIntangibleAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="AmortizationOfIntangibleAssets" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to AmortizationOfIntangibleAssets" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="AmortizationOfFinancingCosts" xlink:title="AmortizationOfFinancingCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="AmortizationOfFinancingCosts" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to AmortizationOfFinancingCosts" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DepreciationAndOtherAmortization" xlink:label="DepreciationAndOtherAmortization" xlink:title="DepreciationAndOtherAmortization" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="DepreciationAndOtherAmortization" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to DepreciationAndOtherAmortization" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="DeferredIncomeTaxExpenseBenefit" xlink:title="DeferredIncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="DeferredIncomeTaxExpenseBenefit" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to DeferredIncomeTaxExpenseBenefit" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccretionExpense" xlink:label="AccretionExpense" xlink:title="AccretionExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="AccretionExpense" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to AccretionExpense" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to IncomeLossFromEquityMethodInvestments" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:label="EquityMethodInvestmentDividendsOrDistributions" xlink:title="EquityMethodInvestmentDividendsOrDistributions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="EquityMethodInvestmentDividendsOrDistributions" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to EquityMethodInvestmentDividendsOrDistributions" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TaxBenefitFromStockOptionsExercised" xlink:label="TaxBenefitFromStockOptionsExercised" xlink:title="TaxBenefitFromStockOptionsExercised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="TaxBenefitFromStockOptionsExercised" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to TaxBenefitFromStockOptionsExercised" use="optional" order="80.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="ShareBasedCompensation" xlink:title="ShareBasedCompensation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="ShareBasedCompensation" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to ShareBasedCompensation" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_AffiliateEquityExpense" xlink:label="AffiliateEquityExpense" xlink:title="AffiliateEquityExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="AffiliateEquityExpense" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to AffiliateEquityExpense" use="optional" order="100.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="OtherNoncashIncomeExpense" xlink:title="OtherNoncashIncomeExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="OtherNoncashIncomeExpense" xlink:title="definition: AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract to OtherNoncashIncomeExpense" use="optional" order="110.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="IncreaseDecreaseInOperatingCapitalAbstract" xlink:title="IncreaseDecreaseInOperatingCapitalAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="IncreaseDecreaseInOperatingCapitalAbstract" xlink:title="definition: NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract to IncreaseDecreaseInOperatingCapitalAbstract" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="IncreaseDecreaseInAccountsReceivable" xlink:title="IncreaseDecreaseInAccountsReceivable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInAccountsReceivable" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInAccountsReceivable" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:title="IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="IncreaseDecreaseInOtherOperatingAssets" xlink:title="IncreaseDecreaseInOtherOperatingAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInOtherOperatingAssets" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInOtherOperatingAssets" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncreaseDecreaseInUnsettledFundSharesReceivables" xlink:label="IncreaseDecreaseInUnsettledFundSharesReceivables" xlink:title="IncreaseDecreaseInUnsettledFundSharesReceivables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInUnsettledFundSharesReceivables" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInUnsettledFundSharesReceivables" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncreaseDecreaseInUnsettledFundSharesPayables" xlink:label="IncreaseDecreaseInUnsettledFundSharesPayables" xlink:title="IncreaseDecreaseInUnsettledFundSharesPayables" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInUnsettledFundSharesPayables" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInUnsettledFundSharesPayables" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingLiabilities" xlink:label="IncreaseDecreaseInOperatingLiabilities" xlink:title="IncreaseDecreaseInOperatingLiabilities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInOperatingLiabilities" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInOperatingLiabilities" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncreaseDecreaseInAffiliateInvestmentsInPartnerships" xlink:label="IncreaseDecreaseInAffiliateInvestmentsInPartnerships" xlink:title="IncreaseDecreaseInAffiliateInvestmentsInPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="IncreaseDecreaseInAffiliateInvestmentsInPartnerships" xlink:title="definition: IncreaseDecreaseInOperatingCapitalAbstract to IncreaseDecreaseInAffiliateInvestmentsInPartnerships" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:title="NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:title="definition: NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract to NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:label="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:title="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:title="definition: StatementLineItems to NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:label="PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:title="PaymentsToAcquireInterestInSubsidiariesAndAffiliates" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsToAcquireInterestInSubsidiariesAndAffiliates" xlink:title="definition: NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract to PaymentsToAcquireInterestInSubsidiariesAndAffiliates" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="PaymentsToAcquirePropertyPlantAndEquipment" xlink:title="PaymentsToAcquirePropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsToAcquirePropertyPlantAndEquipment" xlink:title="definition: NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract to PaymentsToAcquirePropertyPlantAndEquipment" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireMarketableSecurities" xlink:label="PaymentsToAcquireMarketableSecurities" xlink:title="PaymentsToAcquireMarketableSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsToAcquireMarketableSecurities" xlink:title="definition: NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract to PaymentsToAcquireMarketableSecurities" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:label="ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:title="ProceedsFromSaleAndMaturityOfMarketableSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:title="definition: NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract to ProceedsFromSaleAndMaturityOfMarketableSecurities" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:title="NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:title="definition: NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract to NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:label="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:title="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:title="definition: StatementLineItems to NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromLongTermLinesOfCredit" xlink:label="ProceedsFromLongTermLinesOfCredit" xlink:title="ProceedsFromLongTermLinesOfCredit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromLongTermLinesOfCredit" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedsFromLongTermLinesOfCredit" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="RepaymentsOfLongTermLinesOfCredit" xlink:title="RepaymentsOfLongTermLinesOfCredit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="RepaymentsOfLongTermLinesOfCredit" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to RepaymentsOfLongTermLinesOfCredit" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="ProceedsFromIssuanceOfCommonStock" xlink:title="ProceedsFromIssuanceOfCommonStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromIssuanceOfCommonStock" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedsFromIssuanceOfCommonStock" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="PaymentsForRepurchaseOfCommonStock" xlink:title="PaymentsForRepurchaseOfCommonStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsForRepurchaseOfCommonStock" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to PaymentsForRepurchaseOfCommonStock" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="PaymentsOfFinancingCosts" xlink:title="PaymentsOfFinancingCosts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsOfFinancingCosts" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to PaymentsOfFinancingCosts" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:title="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ProceedFromSettlementOfForwardEquitySaleAgreement" xlink:label="ProceedFromSettlementOfForwardEquitySaleAgreement" xlink:title="ProceedFromSettlementOfForwardEquitySaleAgreement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedFromSettlementOfForwardEquitySaleAgreement" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedFromSettlementOfForwardEquitySaleAgreement" use="optional" order="80.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfOtherLongTermDebt" xlink:label="ProceedsFromRepaymentsOfOtherLongTermDebt" xlink:title="ProceedsFromRepaymentsOfOtherLongTermDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromRepaymentsOfOtherLongTermDebt" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedsFromRepaymentsOfOtherLongTermDebt" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsOfDividendsMinorityInterest" xlink:label="PaymentsOfDividendsMinorityInterest" xlink:title="PaymentsOfDividendsMinorityInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsOfDividendsMinorityInterest" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to PaymentsOfDividendsMinorityInterest" use="optional" order="100.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ProceedsFromPaymentsForAffiliateEquityIssuancesAndRepurchases" xlink:label="ProceedsFromPaymentsForAffiliateEquityIssuancesAndRepurchases" xlink:title="ProceedsFromPaymentsForAffiliateEquityIssuancesAndRepurchases" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromPaymentsForAffiliateEquityIssuancesAndRepurchases" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedsFromPaymentsForAffiliateEquityIssuancesAndRepurchases" use="optional" order="110.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:title="NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" use="optional" order="120.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ProceedsFromIssuanceOfJuniorConvertibleDebt" xlink:label="ProceedsFromIssuanceOfJuniorConvertibleDebt" xlink:title="ProceedsFromIssuanceOfJuniorConvertibleDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromIssuanceOfJuniorConvertibleDebt" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedsFromIssuanceOfJuniorConvertibleDebt" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ProceedsFromIssuanceOfSeniorConvertibleDebt" xlink:label="ProceedsFromIssuanceOfSeniorConvertibleDebt" xlink:title="ProceedsFromIssuanceOfSeniorConvertibleDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="ProceedsFromIssuanceOfSeniorConvertibleDebt" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to ProceedsFromIssuanceOfSeniorConvertibleDebt" use="optional" order="8010.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RepaymentsOfConvertibleDebt" xlink:label="RepaymentsOfConvertibleDebt" xlink:title="RepaymentsOfConvertibleDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="RepaymentsOfConvertibleDebt" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to RepaymentsOfConvertibleDebt" use="optional" order="8020.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToMinorityShareholders" xlink:label="PaymentsToMinorityShareholders" xlink:title="PaymentsToMinorityShareholders" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsToMinorityShareholders" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to PaymentsToMinorityShareholders" use="optional" order="8030.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EarlyRepaymentOfJuniorConvertibleTrustPreferredSecurities" xlink:label="EarlyRepaymentOfJuniorConvertibleTrustPreferredSecurities" xlink:title="EarlyRepaymentOfJuniorConvertibleTrustPreferredSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="EarlyRepaymentOfJuniorConvertibleTrustPreferredSecurities" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to EarlyRepaymentOfJuniorConvertibleTrustPreferredSecurities" use="optional" order="8040.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsForProceedsFromHedgeFinancingActivities" xlink:label="PaymentsForProceedsFromHedgeFinancingActivities" xlink:title="PaymentsForProceedsFromHedgeFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="PaymentsForProceedsFromHedgeFinancingActivities" xlink:title="definition: NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract to PaymentsForProceedsFromHedgeFinancingActivities" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" xlink:label="EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" xlink:title="EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" xlink:title="definition: StatementLineItems to EffectOfExchangeRateOnCashAndCashEquivalentsContinuingOperations" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInContinuingOperations" xlink:label="NetCashProvidedByUsedInContinuingOperations" xlink:title="NetCashProvidedByUsedInContinuingOperations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="NetCashProvidedByUsedInContinuingOperations" xlink:title="definition: StatementLineItems to NetCashProvidedByUsedInContinuingOperations" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="CashAndCashEquivalentsAtCarryingValue" xlink:title="CashAndCashEquivalentsAtCarryingValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CashAndCashEquivalentsAtCarryingValue" xlink:title="definition: StatementLineItems to CashAndCashEquivalentsAtCarryingValue" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="SupplementalCashFlowInformationAbstract" xlink:title="SupplementalCashFlowInformationAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="SupplementalCashFlowInformationAbstract" xlink:title="definition: StatementLineItems to SupplementalCashFlowInformationAbstract" use="optional" order="80.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestPaidNet" xlink:label="InterestPaidNet" xlink:title="InterestPaidNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SupplementalCashFlowInformationAbstract" xlink:to="InterestPaidNet" xlink:title="definition: SupplementalCashFlowInformationAbstract to InterestPaidNet" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxesPaidNet" xlink:label="IncomeTaxesPaidNet" xlink:title="IncomeTaxesPaidNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SupplementalCashFlowInformationAbstract" xlink:to="IncomeTaxesPaidNet" xlink:title="definition: SupplementalCashFlowInformationAbstract to IncomeTaxesPaidNet" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:title="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:title="definition: StatementLineItems to CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" use="optional" order="90.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_NotesReceivedForAffiliateEquitySales" xlink:label="NotesReceivedForAffiliateEquitySales" xlink:title="NotesReceivedForAffiliateEquitySales" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="NotesReceivedForAffiliateEquitySales" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to NotesReceivedForAffiliateEquitySales" use="optional" order="8020.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_PayablesRecordedForAffiliateEquityPurchases" xlink:label="PayablesRecordedForAffiliateEquityPurchases" xlink:title="PayablesRecordedForAffiliateEquityPurchases" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="PayablesRecordedForAffiliateEquityPurchases" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to PayablesRecordedForAffiliateEquityPurchases" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_PayablesRecordedUnderContingentPaymentArrangements" xlink:label="PayablesRecordedUnderContingentPaymentArrangements" xlink:title="PayablesRecordedUnderContingentPaymentArrangements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="PayablesRecordedUnderContingentPaymentArrangements" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to PayablesRecordedUnderContingentPaymentArrangements" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedForConversionOfZeroCouponSeniorConvertibleNote" xlink:label="StockIssuedForConversionOfZeroCouponSeniorConvertibleNote" xlink:title="StockIssuedForConversionOfZeroCouponSeniorConvertibleNote" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="StockIssuedForConversionOfZeroCouponSeniorConvertibleNote" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to StockIssuedForConversionOfZeroCouponSeniorConvertibleNote" use="optional" order="30.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedForInvestmentsInAffiliates" xlink:label="StockIssuedForInvestmentsInAffiliates" xlink:title="StockIssuedForInvestmentsInAffiliates" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="StockIssuedForInvestmentsInAffiliates" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to StockIssuedForInvestmentsInAffiliates" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedForSettlementOfForwardEquitySaleAgreement" xlink:label="StockIssuedForSettlementOfForwardEquitySaleAgreement" xlink:title="StockIssuedForSettlementOfForwardEquitySaleAgreement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="StockIssuedForSettlementOfForwardEquitySaleAgreement" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to StockIssuedForSettlementOfForwardEquitySaleAgreement" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedForConversionOfFloatingRateSeniorConvertibleSecurities" xlink:label="StockIssuedForConversionOfFloatingRateSeniorConvertibleSecurities" xlink:title="StockIssuedForConversionOfFloatingRateSeniorConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="StockIssuedForConversionOfFloatingRateSeniorConvertibleSecurities" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to StockIssuedForConversionOfFloatingRateSeniorConvertibleSecurities" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_StockIssuedInSettlementOfMandatoryConvertibleSecurities" xlink:label="StockIssuedInSettlementOfMandatoryConvertibleSecurities" xlink:title="StockIssuedInSettlementOfMandatoryConvertibleSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:to="StockIssuedInSettlementOfMandatoryConvertibleSecurities" xlink:title="definition: CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract to StockIssuedInSettlementOfMandatoryConvertibleSecurities" use="optional" order="8010.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/StatementOfComprehensiveIncome">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="10.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="StatementScenarioAxis" xlink:title="StatementScenarioAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementScenarioAxis" xlink:title="definition: StatementTable to StatementScenarioAxis" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="ScenarioUnspecifiedDomain" xlink:title="ScenarioUnspecifiedDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementScenarioAxis" xlink:to="ScenarioUnspecifiedDomain" xlink:title="definition: StatementScenarioAxis to ScenarioUnspecifiedDomain" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ProfitLoss" xlink:title="definition: StatementLineItems to ProfitLoss" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" xlink:title="definition: StatementLineItems to OtherComprehensiveIncomeLossNetOfTaxPeriodIncreaseDecrease" use="optional" order="40.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:label="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:title="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest" use="optional" order="50.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:label="ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:title="ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" xlink:title="definition: StatementLineItems to ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest" use="optional" order="60.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="ComprehensiveIncomeNetOfTax" xlink:title="ComprehensiveIncomeNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ComprehensiveIncomeNetOfTax" xlink:title="definition: StatementLineItems to ComprehensiveIncomeNetOfTax" use="optional" order="70.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:label="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:title="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:title="definition: StatementLineItems to ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" order="30.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease" xlink:title="definition: ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract to OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPeriodIncreaseDecrease" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease" xlink:title="definition: ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract to OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease" use="optional" order="20.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentNetOfTaxPeriodIncreaseDecrease" xlink:label="OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentNetOfTaxPeriodIncreaseDecrease" xlink:title="OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentNetOfTaxPeriodIncreaseDecrease" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentNetOfTaxPeriodIncreaseDecrease" xlink:title="definition: ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestAbstract to OtherComprehensiveIncomeAvailableForSaleSecuritiesAdjustmentNetOfTaxPeriodIncreaseDecrease" use="optional" order="30.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureComprehensiveIncomeDetails2">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementLineItems" xlink:label="StatementLineItems" xlink:title="StatementLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementTable" xlink:label="StatementTable" xlink:title="StatementTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementLineItems" xlink:to="StatementTable" xlink:title="definition: StatementLineItems to StatementTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="StatementEquityComponentsAxis" xlink:title="StatementEquityComponentsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementTable" xlink:to="StatementEquityComponentsAxis" xlink:title="definition: StatementTable to StatementEquityComponentsAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="EquityComponentDomain" xlink:title="EquityComponentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementEquityComponentsAxis" xlink:to="EquityComponentDomain" xlink:title="definition: StatementEquityComponentsAxis to EquityComponentDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedTranslationAdjustmentMember" xlink:label="AccumulatedTranslationAdjustmentMember" xlink:title="AccumulatedTranslationAdjustmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedTranslationAdjustmentMember" xlink:title="definition: EquityComponentDomain to AccumulatedTranslationAdjustmentMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:label="AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:title="AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" xlink:title="definition: EquityComponentDomain to AccumulatedNetGainLossFromDesignatedOrQualifyingCashFlowHedgesMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:label="AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:title="AccumulatedNetUnrealizedInvestmentGainLossMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:title="definition: EquityComponentDomain to AccumulatedNetUnrealizedInvestmentGainLossMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="AccumulatedOtherComprehensiveIncomeMember" xlink:title="AccumulatedOtherComprehensiveIncomeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EquityComponentDomain" xlink:to="AccumulatedOtherComprehensiveIncomeMember" xlink:title="definition: EquityComponentDomain to AccumulatedOtherComprehensiveIncomeMember" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax" xlink:title="definition: StatementLineItems to AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" xlink:title="definition: StatementLineItems to AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInNetGainLossFromCashFlowHedgesEffectNetOfTax" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:title="definition: StatementLineItems to AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementLineItems" xlink:to="AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:title="definition: StatementLineItems to AccumulatedOtherComprehensiveIncomeLossNetOfTax" use="optional" order="5.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureStockholdersEquityDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockMember" xlink:label="CommonStockMember" xlink:title="CommonStockMember" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonClassAMember" xlink:label="CommonClassAMember" xlink:title="CommonClassAMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommonStockMember" xlink:to="CommonClassAMember" xlink:title="definition: CommonStockMember to CommonClassAMember" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonClassBMember" xlink:label="CommonClassBMember" xlink:title="CommonClassBMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommonStockMember" xlink:to="CommonClassBMember" xlink:title="definition: CommonStockMember to CommonClassBMember" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassOfStockLineItems" xlink:label="ClassOfStockLineItems" xlink:title="ClassOfStockLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="ScheduleOfStockByClassTable" xlink:title="ScheduleOfStockByClassTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ClassOfStockLineItems" xlink:to="ScheduleOfStockByClassTable" xlink:title="definition: ClassOfStockLineItems to ScheduleOfStockByClassTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="StatementClassOfStockAxis" xlink:title="StatementClassOfStockAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfStockByClassTable" xlink:to="StatementClassOfStockAxis" xlink:title="definition: ScheduleOfStockByClassTable to StatementClassOfStockAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain" xlink:title="ClassOfStockDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="ClassOfStockDomain_2" xlink:title="ClassOfStockDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementClassOfStockAxis" xlink:to="ClassOfStockDomain_2" xlink:title="definition: StatementClassOfStockAxis to ClassOfStockDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PreferredStockMember" xlink:label="PreferredStockMember" xlink:title="PreferredStockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="PreferredStockMember" xlink:title="definition: ClassOfStockDomain to PreferredStockMember" use="optional" order="8000.0" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockDomain" xlink:to="CommonStockMember" xlink:title="definition: ClassOfStockDomain to CommonStockMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="PreferredStockSharesAuthorized" xlink:title="PreferredStockSharesAuthorized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="PreferredStockSharesAuthorized" xlink:title="definition: ClassOfStockLineItems to PreferredStockSharesAuthorized" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:label="StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:title="StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" xlink:title="definition: ClassOfStockLineItems to StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" xlink:label="TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" xlink:title="TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" xlink:title="definition: ClassOfStockLineItems to TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockSharesAcquired" xlink:label="TreasuryStockSharesAcquired" xlink:title="TreasuryStockSharesAcquired" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" xlink:to="TreasuryStockSharesAcquired" xlink:title="definition: TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract to TreasuryStockSharesAcquired" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare" xlink:label="TreasuryStockAcquiredAverageCostPerShare" xlink:title="TreasuryStockAcquiredAverageCostPerShare" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract" xlink:to="TreasuryStockAcquiredAverageCostPerShare" xlink:title="definition: TreasuryStockTransactionsExcludingValueOfSharesReissuedAbstract to TreasuryStockAcquiredAverageCostPerShare" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="CommonStockSharesAuthorized" xlink:title="CommonStockSharesAuthorized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassOfStockLineItems" xlink:to="CommonStockSharesAuthorized" xlink:title="definition: ClassOfStockLineItems to CommonStockSharesAuthorized" use="optional" order="5.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureSegmentInformationDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="OperatingExpensesAbstract" xlink:title="OperatingExpensesAbstract" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="OperatingExpenses" xlink:title="OperatingExpenses" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="OperatingExpenses" xlink:title="definition: OperatingExpensesAbstract to OperatingExpenses" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="DepreciationDepletionAndAmortization" xlink:title="DepreciationDepletionAndAmortization" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="DepreciationDepletionAndAmortization" xlink:title="definition: OperatingExpensesAbstract to DepreciationDepletionAndAmortization" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_OperatingExpensesOther" xlink:label="OperatingExpensesOther" xlink:title="OperatingExpensesOther" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="OperatingExpensesAbstract" xlink:to="OperatingExpensesOther" xlink:title="definition: OperatingExpensesAbstract to OperatingExpensesOther" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NonoperatingIncomeExpenseAbstract" xlink:label="NonoperatingIncomeExpenseAbstract" xlink:title="NonoperatingIncomeExpenseAbstract" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentAndOtherIncomeLoss" xlink:label="InvestmentAndOtherIncomeLoss" xlink:title="InvestmentAndOtherIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="InvestmentAndOtherIncomeLoss" xlink:title="definition: NonoperatingIncomeExpenseAbstract to InvestmentAndOtherIncomeLoss" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="IncomeLossFromEquityMethodInvestments" xlink:title="IncomeLossFromEquityMethodInvestments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="IncomeLossFromEquityMethodInvestments" xlink:title="definition: NonoperatingIncomeExpenseAbstract to IncomeLossFromEquityMethodInvestments" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentIncomeLossFromInvestmentsInPartnerships" xlink:label="InvestmentIncomeLossFromInvestmentsInPartnerships" xlink:title="InvestmentIncomeLossFromInvestmentsInPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="InvestmentIncomeLossFromInvestmentsInPartnerships" xlink:title="definition: NonoperatingIncomeExpenseAbstract to InvestmentIncomeLossFromInvestmentsInPartnerships" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NonoperatingIncomeExpense" xlink:label="NonoperatingIncomeExpense" xlink:title="NonoperatingIncomeExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="NonoperatingIncomeExpense" xlink:title="definition: NonoperatingIncomeExpenseAbstract to NonoperatingIncomeExpense" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ImputedInterestAndInterestExpense" xlink:label="ImputedInterestAndInterestExpense" xlink:title="ImputedInterestAndInterestExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonoperatingIncomeExpenseAbstract" xlink:to="ImputedInterestAndInterestExpense" xlink:title="definition: NonoperatingIncomeExpenseAbstract to ImputedInterestAndInterestExpense" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="SegmentReportingInformationLineItems" xlink:title="SegmentReportingInformationLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:title="ScheduleOfSegmentReportingInformationBySegmentTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="SegmentReportingInformationLineItems" xlink:to="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:title="definition: SegmentReportingInformationLineItems to ScheduleOfSegmentReportingInformationBySegmentTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfSegmentReportingInformationBySegmentTable to StatementBusinessSegmentsAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain_2" xlink:title="SegmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain_2" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_MutualFundMember" xlink:label="MutualFundMember" xlink:title="MutualFundMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="MutualFundMember" xlink:title="definition: SegmentDomain to MutualFundMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InstitutionalMember" xlink:label="InstitutionalMember" xlink:title="InstitutionalMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InstitutionalMember" xlink:title="definition: SegmentDomain to InstitutionalMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_HighNetWorthMember" xlink:label="HighNetWorthMember" xlink:title="HighNetWorthMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="HighNetWorthMember" xlink:title="definition: SegmentDomain to HighNetWorthMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SegmentIncomeStatementAbstract" xlink:label="SegmentIncomeStatementAbstract" xlink:title="SegmentIncomeStatementAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="SegmentIncomeStatementAbstract" xlink:title="definition: SegmentReportingInformationLineItems to SegmentIncomeStatementAbstract" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetManagementFees" xlink:label="AssetManagementFees" xlink:title="AssetManagementFees" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="AssetManagementFees" xlink:title="definition: SegmentIncomeStatementAbstract to AssetManagementFees" use="optional" order="1.0" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="OperatingExpensesAbstract" xlink:title="definition: SegmentIncomeStatementAbstract to OperatingExpensesAbstract" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="OperatingIncomeLoss" xlink:title="OperatingIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="OperatingIncomeLoss" xlink:title="definition: SegmentIncomeStatementAbstract to OperatingIncomeLoss" use="optional" order="3.0" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="NonoperatingIncomeExpenseAbstract" xlink:title="definition: SegmentIncomeStatementAbstract to NonoperatingIncomeExpenseAbstract" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:title="definition: SegmentIncomeStatementAbstract to IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: SegmentIncomeStatementAbstract to IncomeTaxExpenseBenefit" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="ProfitLoss" xlink:title="definition: SegmentIncomeStatementAbstract to ProfitLoss" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:label="MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:title="MinorityInterestInNetIncomeLossOtherMinorityInterests" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:title="definition: SegmentIncomeStatementAbstract to MinorityInterestInNetIncomeLossOtherMinorityInterests" use="optional" order="8.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinorityInterestInNetIncomeLossOperatingPartnerships" xlink:label="MinorityInterestInNetIncomeLossOperatingPartnerships" xlink:title="MinorityInterestInNetIncomeLossOperatingPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="MinorityInterestInNetIncomeLossOperatingPartnerships" xlink:title="definition: SegmentIncomeStatementAbstract to MinorityInterestInNetIncomeLossOperatingPartnerships" use="optional" order="9.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="NetIncomeLoss" xlink:title="NetIncomeLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentIncomeStatementAbstract" xlink:to="NetIncomeLoss" xlink:title="definition: SegmentIncomeStatementAbstract to NetIncomeLoss" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SegmentFinancialPositionAbstract" xlink:label="SegmentFinancialPositionAbstract" xlink:title="SegmentFinancialPositionAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentReportingInformationLineItems" xlink:to="SegmentFinancialPositionAbstract" xlink:title="definition: SegmentReportingInformationLineItems to SegmentFinancialPositionAbstract" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Assets" xlink:label="Assets" xlink:title="Assets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentFinancialPositionAbstract" xlink:to="Assets" xlink:title="definition: SegmentFinancialPositionAbstract to Assets" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentFinancialPositionAbstract" xlink:to="Goodwill" xlink:title="definition: SegmentFinancialPositionAbstract to Goodwill" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="EquityMethodInvestments" xlink:title="EquityMethodInvestments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentFinancialPositionAbstract" xlink:to="EquityMethodInvestments" xlink:title="definition: SegmentFinancialPositionAbstract to EquityMethodInvestments" use="optional" order="3.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureGoodwillAndAcquiredClientRelationshipsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_MutualFundMember" xlink:label="MutualFundMember" xlink:title="MutualFundMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="MutualFundMember" xlink:title="definition: SegmentDomain to MutualFundMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InstitutionalMember" xlink:label="InstitutionalMember" xlink:title="InstitutionalMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InstitutionalMember" xlink:title="definition: SegmentDomain to InstitutionalMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_HighNetWorthMember" xlink:label="HighNetWorthMember" xlink:title="HighNetWorthMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="HighNetWorthMember" xlink:title="definition: SegmentDomain to HighNetWorthMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GoodwillLineItems" xlink:label="GoodwillLineItems" xlink:title="GoodwillLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfGoodwillTable" xlink:label="ScheduleOfGoodwillTable" xlink:title="ScheduleOfGoodwillTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="GoodwillLineItems" xlink:to="ScheduleOfGoodwillTable" xlink:title="definition: GoodwillLineItems to ScheduleOfGoodwillTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfGoodwillTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfGoodwillTable to StatementBusinessSegmentsAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GoodwillRollForward" xlink:label="GoodwillRollForward" xlink:title="GoodwillRollForward" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillLineItems" xlink:to="GoodwillRollForward" xlink:title="definition: GoodwillLineItems to GoodwillRollForward" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="Goodwill" xlink:title="definition: GoodwillRollForward to Goodwill" use="optional" priority="1" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:label="GoodwillAcquiredDuringPeriod" xlink:title="GoodwillAcquiredDuringPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillAcquiredDuringPeriod" xlink:title="definition: GoodwillRollForward to GoodwillAcquiredDuringPeriod" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GoodwillTranslationAdjustments" xlink:label="GoodwillTranslationAdjustments" xlink:title="GoodwillTranslationAdjustments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillTranslationAdjustments" xlink:title="definition: GoodwillRollForward to GoodwillTranslationAdjustments" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments" xlink:label="GoodwillPurchaseAccountingAdjustments" xlink:title="GoodwillPurchaseAccountingAdjustments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GoodwillRollForward" xlink:to="GoodwillPurchaseAccountingAdjustments" xlink:title="definition: GoodwillRollForward to GoodwillPurchaseAccountingAdjustments" order="8000.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureBusinessCombinationsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="StatementBusinessSegmentsAxis" xlink:title="StatementBusinessSegmentsAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentDomain" xlink:label="SegmentDomain" xlink:title="SegmentDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="StatementBusinessSegmentsAxis" xlink:to="SegmentDomain" xlink:title="definition: StatementBusinessSegmentsAxis to SegmentDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_MutualFundMember" xlink:label="MutualFundMember" xlink:title="MutualFundMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="MutualFundMember" xlink:title="definition: SegmentDomain to MutualFundMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InstitutionalMember" xlink:label="InstitutionalMember" xlink:title="InstitutionalMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="InstitutionalMember" xlink:title="definition: SegmentDomain to InstitutionalMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_HighNetWorthMember" xlink:label="HighNetWorthMember" xlink:title="HighNetWorthMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentDomain" xlink:to="HighNetWorthMember" xlink:title="definition: SegmentDomain to HighNetWorthMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="BusinessAcquisitionLineItems" xlink:title="BusinessAcquisitionLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="BusinessAcquisitionLineItems" xlink:to="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:title="definition: BusinessAcquisitionLineItems to ScheduleOfBusinessAcquisitionsByAcquisitionTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to BusinessAcquisitionAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain_2" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain_2" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_PantheonMember" xlink:label="PantheonMember" xlink:title="PantheonMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="PantheonMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to PantheonMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ArtemisMember" xlink:label="ArtemisMember" xlink:title="ArtemisMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="ArtemisMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to ArtemisMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_AstonMember" xlink:label="AstonMember" xlink:title="AstonMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="AstonMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to AstonMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_TrilogyMember" xlink:label="TrilogyMember" xlink:title="TrilogyMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="TrilogyMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to TrilogyMember" use="optional" order="4.0" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="StatementBusinessSegmentsAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to StatementBusinessSegmentsAxis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="LegalEntityAxis" xlink:title="definition: ScheduleOfBusinessAcquisitionsByAcquisitionTable to LegalEntityAxis" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EntityDomain to NoncontrollingInterestMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_AcquiredGoodwillAndClientRelationshipsAmortizationPeriodForTaxDeductions" xlink:label="AcquiredGoodwillAndClientRelationshipsAmortizationPeriodForTaxDeductions" xlink:title="AcquiredGoodwillAndClientRelationshipsAmortizationPeriodForTaxDeductions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="AcquiredGoodwillAndClientRelationshipsAmortizationPeriodForTaxDeductions" xlink:title="definition: BusinessAcquisitionLineItems to AcquiredGoodwillAndClientRelationshipsAmortizationPeriodForTaxDeductions" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:label="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:title="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueLow" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessAcquisitionContingentConsiderationPayments" xlink:label="BusinessAcquisitionContingentConsiderationPayments" xlink:title="BusinessAcquisitionContingentConsiderationPayments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionContingentConsiderationPayments" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionContingentConsiderationPayments" use="optional" order="8.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessAcquisitionContingentConsiderationProjectedPayments" xlink:label="BusinessAcquisitionContingentConsiderationProjectedPayments" xlink:title="BusinessAcquisitionContingentConsiderationProjectedPayments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionContingentConsiderationProjectedPayments" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionContingentConsiderationProjectedPayments" use="optional" order="9.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" xlink:label="BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" xlink:title="BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationLiabilitiesArisingFromContingenciesAmountRecognized" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAcquisitionMinimum" xlink:label="BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAcquisitionMinimum" xlink:title="BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAcquisitionMinimum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAcquisitionMinimum" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAcquisitionMinimum" use="optional" order="11.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAquisitionMaximum" xlink:label="BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAquisitionMaximum" xlink:title="BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAquisitionMaximum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAquisitionMaximum" xlink:title="definition: BusinessAcquisitionLineItems to BusinessCombinationLiabilitiesArisingFromContingenciesAmountToBeRecognizedAfterPeriodOfAquisitionMaximum" use="optional" order="12.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_NumberOfNoLoadMutualFunds" xlink:label="NumberOfNoLoadMutualFunds" xlink:title="NumberOfNoLoadMutualFunds" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="NumberOfNoLoadMutualFunds" xlink:title="definition: BusinessAcquisitionLineItems to NumberOfNoLoadMutualFunds" use="optional" order="13.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_NumberOfYearsExperience" xlink:label="NumberOfYearsExperience" xlink:title="NumberOfYearsExperience" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="NumberOfYearsExperience" xlink:title="definition: BusinessAcquisitionLineItems to NumberOfYearsExperience" use="optional" order="14.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:label="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:title="BusinessAcquisitionPurchasePriceAllocationAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionPurchasePriceAllocationAbstract" use="optional" order="15.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessAcquisitionDeferredConsideration" xlink:label="BusinessAcquisitionDeferredConsideration" xlink:title="BusinessAcquisitionDeferredConsideration" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionDeferredConsideration" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionDeferredConsideration" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessAcquisitionEnterpriseValue" xlink:label="BusinessAcquisitionEnterpriseValue" xlink:title="BusinessAcquisitionEnterpriseValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionEnterpriseValue" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionEnterpriseValue" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets" xlink:label="BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets" xlink:title="BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssets" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationDeferredIncomeTaxesAssetLiabilityNet" xlink:label="BusinessAcquisitionPurchasePriceAllocationDeferredIncomeTaxesAssetLiabilityNet" xlink:title="BusinessAcquisitionPurchasePriceAllocationDeferredIncomeTaxesAssetLiabilityNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionPurchasePriceAllocationDeferredIncomeTaxesAssetLiabilityNet" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionPurchasePriceAllocationDeferredIncomeTaxesAssetLiabilityNet" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNet" xlink:label="BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNet" xlink:title="BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNet" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionPurchasePriceAllocationAssetsAcquiredLiabilitiesAssumedNet" use="optional" order="8.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityCashPaid" xlink:label="BusinessAcquisitionCostOfAcquiredEntityCashPaid" xlink:title="BusinessAcquisitionCostOfAcquiredEntityCashPaid" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionCostOfAcquiredEntityCashPaid" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionCostOfAcquiredEntityCashPaid" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:title="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionPurchasePriceAllocationTangibleAssets" xlink:label="BusinessAcquisitionPurchasePriceAllocationTangibleAssets" xlink:title="BusinessAcquisitionPurchasePriceAllocationTangibleAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionPurchasePriceAllocationAbstract" xlink:to="BusinessAcquisitionPurchasePriceAllocationTangibleAssets" xlink:title="definition: BusinessAcquisitionPurchasePriceAllocationAbstract to BusinessAcquisitionPurchasePriceAllocationTangibleAssets" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BusinessAcquisitionPurchasePriceAllocationGoodwillPercentage" xlink:label="BusinessAcquisitionPurchasePriceAllocationGoodwillPercentage" xlink:title="BusinessAcquisitionPurchasePriceAllocationGoodwillPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionLineItems" xlink:to="BusinessAcquisitionPurchasePriceAllocationGoodwillPercentage" xlink:title="definition: BusinessAcquisitionLineItems to BusinessAcquisitionPurchasePriceAllocationGoodwillPercentage" use="optional" order="3.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureCommitmentsAndContingenciesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="BusinessAcquisitionAxis" xlink:title="BusinessAcquisitionAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="BusinessAcquisitionAcquireeDomain" xlink:title="BusinessAcquisitionAcquireeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessAcquisitionAxis" xlink:to="BusinessAcquisitionAcquireeDomain" xlink:title="definition: BusinessAcquisitionAxis to BusinessAcquisitionAcquireeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_PantheonMember" xlink:label="PantheonMember" xlink:title="PantheonMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessAcquisitionAcquireeDomain" xlink:to="PantheonMember" xlink:title="definition: BusinessAcquisitionAcquireeDomain to PantheonMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_RussellMember" xlink:label="RussellMember" xlink:title="RussellMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="RussellMember" xlink:title="definition: EntityDomain to RussellMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CommitmentAndContingenciesLineItems" xlink:label="CommitmentAndContingenciesLineItems" xlink:title="CommitmentAndContingenciesLineItems" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CommitmentAndContingenciesTable" xlink:label="CommitmentAndContingenciesTable" xlink:title="CommitmentAndContingenciesTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CommitmentAndContingenciesLineItems" xlink:to="CommitmentAndContingenciesTable" xlink:title="definition: CommitmentAndContingenciesLineItems to CommitmentAndContingenciesTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CommitmentAndContingenciesTable" xlink:to="BusinessAcquisitionAxis" xlink:title="definition: CommitmentAndContingenciesTable to BusinessAcquisitionAxis" use="optional" order="1.0" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CommitmentAndContingenciesTable" xlink:to="LegalEntityAxis" xlink:title="definition: CommitmentAndContingenciesTable to LegalEntityAxis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentCommitmentAmount" xlink:label="InvestmentCommitmentAmount" xlink:title="InvestmentCommitmentAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommitmentAndContingenciesLineItems" xlink:to="InvestmentCommitmentAmount" xlink:title="definition: CommitmentAndContingenciesLineItems to InvestmentCommitmentAmount" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ReimbursableAmountOfInvestmentCommitments" xlink:label="ReimbursableAmountOfInvestmentCommitments" xlink:title="ReimbursableAmountOfInvestmentCommitments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommitmentAndContingenciesLineItems" xlink:to="ReimbursableAmountOfInvestmentCommitments" xlink:title="definition: CommitmentAndContingenciesLineItems to ReimbursableAmountOfInvestmentCommitments" use="optional" order="3.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureIncomeTaxesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain_2" xlink:title="EntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LegalEntityAxis" xlink:to="EntityDomain_2" xlink:title="definition: LegalEntityAxis to EntityDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="NoncontrollingInterestMember" xlink:title="NoncontrollingInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="NoncontrollingInterestMember" xlink:title="definition: EntityDomain to NoncontrollingInterestMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ParentMember" xlink:label="ParentMember" xlink:title="ParentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="ParentMember" xlink:title="definition: EntityDomain to ParentMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncomeTaxLineItems" xlink:label="IncomeTaxLineItems" xlink:title="IncomeTaxLineItems" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncomeTaxProvisionTable" xlink:label="IncomeTaxProvisionTable" xlink:title="IncomeTaxProvisionTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IncomeTaxLineItems" xlink:to="IncomeTaxProvisionTable" xlink:title="definition: IncomeTaxLineItems to IncomeTaxProvisionTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="IncomeTaxProvisionTable" xlink:to="LegalEntityAxis" xlink:title="definition: IncomeTaxProvisionTable to LegalEntityAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="CurrentIncomeTaxExpenseBenefit" xlink:title="CurrentIncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="CurrentIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxLineItems to CurrentIncomeTaxExpenseBenefit" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DeferredIncomeTaxExpenseRelatedToIntangibles" xlink:label="DeferredIncomeTaxExpenseRelatedToIntangibles" xlink:title="DeferredIncomeTaxExpenseRelatedToIntangibles" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="DeferredIncomeTaxExpenseRelatedToIntangibles" xlink:title="definition: IncomeTaxLineItems to DeferredIncomeTaxExpenseRelatedToIntangibles" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredOtherTaxExpenseBenefit" xlink:label="DeferredOtherTaxExpenseBenefit" xlink:title="DeferredOtherTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="DeferredOtherTaxExpenseBenefit" xlink:title="definition: IncomeTaxLineItems to DeferredOtherTaxExpenseBenefit" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="DeferredIncomeTaxExpenseBenefit" xlink:title="DeferredIncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="DeferredIncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxLineItems to DeferredIncomeTaxExpenseBenefit" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="IncomeTaxExpenseBenefit" xlink:title="IncomeTaxExpenseBenefit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="IncomeTaxExpenseBenefit" xlink:title="definition: IncomeTaxLineItems to IncomeTaxExpenseBenefit" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncomeLossFromContinuingOperationsBeforeIncomeTaxesAttributableToParent" xlink:label="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAttributableToParent" xlink:title="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAttributableToParent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="IncomeLossFromContinuingOperationsBeforeIncomeTaxesAttributableToParent" xlink:title="definition: IncomeTaxLineItems to IncomeLossFromContinuingOperationsBeforeIncomeTaxesAttributableToParent" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncomeTaxExpenseFromControllingInterestToPretaxIncomeFromContinuedOperationsAttributableToControllingInterestRatio" xlink:label="IncomeTaxExpenseFromControllingInterestToPretaxIncomeFromContinuedOperationsAttributableToControllingInterestRatio" xlink:title="IncomeTaxExpenseFromControllingInterestToPretaxIncomeFromContinuedOperationsAttributableToControllingInterestRatio" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeTaxLineItems" xlink:to="IncomeTaxExpenseFromControllingInterestToPretaxIncomeFromContinuedOperationsAttributableToControllingInterestRatio" xlink:title="definition: IncomeTaxLineItems to IncomeTaxExpenseFromControllingInterestToPretaxIncomeFromContinuedOperationsAttributableToControllingInterestRatio" use="optional" order="8.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureInvestmentsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_LegalEntityAxis" xlink:label="LegalEntityAxis" xlink:title="LegalEntityAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_EntityDomain" xlink:label="EntityDomain" xlink:title="EntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LegalEntityAxis" xlink:to="EntityDomain" xlink:title="definition: LegalEntityAxis to EntityDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ValuePartnersGroupLimitedMember" xlink:label="ValuePartnersGroupLimitedMember" xlink:title="ValuePartnersGroupLimitedMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="ValuePartnersGroupLimitedMember" xlink:title="definition: EntityDomain to ValuePartnersGroupLimitedMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="ScheduleOfInvestmentsLineItems" xlink:title="ScheduleOfInvestmentsLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="ScheduleOfInvestmentsTable" xlink:title="ScheduleOfInvestmentsTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="ScheduleOfInvestmentsTable" xlink:title="definition: ScheduleOfInvestmentsLineItems to ScheduleOfInvestmentsTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfInvestmentsTable" xlink:to="LegalEntityAxis" xlink:title="definition: ScheduleOfInvestmentsTable to LegalEntityAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrealizedGainLossOnInvestmentsAbstract" xlink:label="UnrealizedGainLossOnInvestmentsAbstract" xlink:title="UnrealizedGainLossOnInvestmentsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfInvestmentsLineItems" xlink:to="UnrealizedGainLossOnInvestmentsAbstract" xlink:title="definition: ScheduleOfInvestmentsLineItems to UnrealizedGainLossOnInvestmentsAbstract" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_MarketableSecuritiesAtCost" xlink:label="MarketableSecuritiesAtCost" xlink:title="MarketableSecuritiesAtCost" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="MarketableSecuritiesAtCost" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to MarketableSecuritiesAtCost" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrealizedGainOnSecurities" xlink:label="UnrealizedGainOnSecurities" xlink:title="UnrealizedGainOnSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="UnrealizedGainOnSecurities" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to UnrealizedGainOnSecurities" use="optional" order="8002.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrealizedLossOnSecurities" xlink:label="UnrealizedLossOnSecurities" xlink:title="UnrealizedLossOnSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="UnrealizedLossOnSecurities" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to UnrealizedLossOnSecurities" use="optional" order="8004.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_MarketableSecuritiesFairValue" xlink:label="MarketableSecuritiesFairValue" xlink:title="MarketableSecuritiesFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="MarketableSecuritiesFairValue" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to MarketableSecuritiesFairValue" use="optional" order="8005.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IncreaseDecreaseInMarketableSecuritiesFairValue" xlink:label="IncreaseDecreaseInMarketableSecuritiesFairValue" xlink:title="IncreaseDecreaseInMarketableSecuritiesFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="IncreaseDecreaseInMarketableSecuritiesFairValue" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to IncreaseDecreaseInMarketableSecuritiesFairValue" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="EquityMethodInvestmentOwnershipPercentage" xlink:title="EquityMethodInvestmentOwnershipPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="EquityMethodInvestmentOwnershipPercentage" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to EquityMethodInvestmentOwnershipPercentage" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MarketableSecuritiesCurrent" xlink:label="MarketableSecuritiesCurrent" xlink:title="MarketableSecuritiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnrealizedGainLossOnInvestmentsAbstract" xlink:to="MarketableSecuritiesCurrent" xlink:title="definition: UnrealizedGainLossOnInvestmentsAbstract to MarketableSecuritiesCurrent" order="1.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureGoodwillAndAcquiredClientRelationshipsDetails2">
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IntangibleAssestLineItems" xlink:label="IntangibleAssestLineItems" xlink:title="IntangibleAssestLineItems" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ScheduleOfIntangibleAssetsByMajorClassTable" xlink:label="ScheduleOfIntangibleAssetsByMajorClassTable" xlink:title="ScheduleOfIntangibleAssetsByMajorClassTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="IntangibleAssestLineItems" xlink:to="ScheduleOfIntangibleAssetsByMajorClassTable" xlink:title="definition: IntangibleAssestLineItems to ScheduleOfIntangibleAssetsByMajorClassTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfIntangibleAssetsByMajorClassTable" xlink:to="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfIntangibleAssetsByMajorClassTable to AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" order="1.0" xbrldt:usable="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="CustomerRelationshipsMember" xlink:title="CustomerRelationshipsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="CustomerRelationshipsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to CustomerRelationshipsMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_AcquiredClientRelationshipsOfEquityMethodInvestmentsMember" xlink:label="AcquiredClientRelationshipsOfEquityMethodInvestmentsMember" xlink:title="AcquiredClientRelationshipsOfEquityMethodInvestmentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="AcquiredClientRelationshipsOfEquityMethodInvestmentsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to AcquiredClientRelationshipsOfEquityMethodInvestmentsMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="IndefiniteLivedIntangibleAssetsByMajorClassAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfIntangibleAssetsByMajorClassTable" xlink:to="IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfIntangibleAssetsByMajorClassTable to IndefiniteLivedIntangibleAssetsByMajorClassAxis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="IndefiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: IndefiniteLivedIntangibleAssetsByMajorClassAxis to IndefiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" order="1.0" xbrldt:usable="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="IndefiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="IndefiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="IndefiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="IndefiniteLivedIntangibleAssetsMajorClassNameDomain_2" xlink:title="definition: IndefiniteLivedIntangibleAssetsByMajorClassAxis to IndefiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_AcquiredClientRelationshipsMutualFundManagementContractMember" xlink:label="AcquiredClientRelationshipsMutualFundManagementContractMember" xlink:title="AcquiredClientRelationshipsMutualFundManagementContractMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndefiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="AcquiredClientRelationshipsMutualFundManagementContractMember" xlink:title="definition: IndefiniteLivedIntangibleAssetsMajorClassNameDomain to AcquiredClientRelationshipsMutualFundManagementContractMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAbstract" xlink:label="FiniteLivedIntangibleAssetsAbstract" xlink:title="FiniteLivedIntangibleAssetsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IntangibleAssestLineItems" xlink:to="FiniteLivedIntangibleAssetsAbstract" xlink:title="definition: IntangibleAssestLineItems to FiniteLivedIntangibleAssetsAbstract" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="FiniteLivedIntangibleAssetsGross" xlink:title="FiniteLivedIntangibleAssetsGross" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAbstract" xlink:to="FiniteLivedIntangibleAssetsGross" xlink:title="definition: FiniteLivedIntangibleAssetsAbstract to FiniteLivedIntangibleAssetsGross" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="FiniteLivedIntangibleAssetsAccumulatedAmortization" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAbstract" xlink:to="FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:title="definition: FiniteLivedIntangibleAssetsAbstract to FiniteLivedIntangibleAssetsAccumulatedAmortization" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Goodwill" xlink:label="Goodwill" xlink:title="Goodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAbstract" xlink:to="Goodwill" xlink:title="definition: FiniteLivedIntangibleAssetsAbstract to Goodwill" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_IndefiniteLivedIntangibleAssetsAbstract" xlink:label="IndefiniteLivedIntangibleAssetsAbstract" xlink:title="IndefiniteLivedIntangibleAssetsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IntangibleAssestLineItems" xlink:to="IndefiniteLivedIntangibleAssetsAbstract" xlink:title="definition: IntangibleAssestLineItems to IndefiniteLivedIntangibleAssetsAbstract" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:label="IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:title="IndefiniteLivedIntangibleAssetsExcludingGoodwill" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IndefiniteLivedIntangibleAssetsAbstract" xlink:to="IndefiniteLivedIntangibleAssetsExcludingGoodwill" xlink:title="definition: IndefiniteLivedIntangibleAssetsAbstract to IndefiniteLivedIntangibleAssetsExcludingGoodwill" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IntangibleAssestLineItems" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:title="definition: IntangibleAssestLineItems to FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpense" xlink:label="FiniteLivedIntangibleAssetsAmortizationExpense" xlink:title="FiniteLivedIntangibleAssetsAmortizationExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:to="FiniteLivedIntangibleAssetsAmortizationExpense" xlink:title="definition: FiniteLivedIntangibleAssetsAmortizationExpenseAbstract to FiniteLivedIntangibleAssetsAmortizationExpense" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsUsefulLife" xlink:label="FiniteLivedIntangibleAssetsUsefulLife" xlink:title="FiniteLivedIntangibleAssetsUsefulLife" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:to="FiniteLivedIntangibleAssetsUsefulLife" xlink:title="definition: FiniteLivedIntangibleAssetsAmortizationExpenseAbstract to FiniteLivedIntangibleAssetsUsefulLife" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FiniteLivedIntangibleAssetsFutureAnnualAmortizationExpense" xlink:label="FiniteLivedIntangibleAssetsFutureAnnualAmortizationExpense" xlink:title="FiniteLivedIntangibleAssetsFutureAnnualAmortizationExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:to="FiniteLivedIntangibleAssetsFutureAnnualAmortizationExpense" xlink:title="definition: FiniteLivedIntangibleAssetsAmortizationExpenseAbstract to FiniteLivedIntangibleAssetsFutureAnnualAmortizationExpense" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_NumberOfFutureAnnualPeriodsOfAmortizationExpensePresented" xlink:label="NumberOfFutureAnnualPeriodsOfAmortizationExpensePresented" xlink:title="NumberOfFutureAnnualPeriodsOfAmortizationExpensePresented" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsAmortizationExpenseAbstract" xlink:to="NumberOfFutureAnnualPeriodsOfAmortizationExpensePresented" xlink:title="definition: FiniteLivedIntangibleAssetsAmortizationExpenseAbstract to NumberOfFutureAnnualPeriodsOfAmortizationExpensePresented" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:label="GoodwillAndIntangibleAssetImpairment" xlink:title="GoodwillAndIntangibleAssetImpairment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IntangibleAssestLineItems" xlink:to="GoodwillAndIntangibleAssetImpairment" xlink:title="definition: IntangibleAssestLineItems to GoodwillAndIntangibleAssetImpairment" order="5.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureEquityInvestmentsInAffiliatesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="FiniteLivedIntangibleAssetsMajorClassNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:to="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:title="definition: AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis to FiniteLivedIntangibleAssetsMajorClassNameDomain" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CustomerRelationshipsMember" xlink:label="CustomerRelationshipsMember" xlink:title="CustomerRelationshipsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:to="CustomerRelationshipsMember" xlink:title="definition: FiniteLivedIntangibleAssetsMajorClassNameDomain to CustomerRelationshipsMember" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="ScheduleOfEquityMethodInvestmentsLineItems" xlink:title="ScheduleOfEquityMethodInvestmentsLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="ScheduleOfEquityMethodInvestmentsTable" xlink:title="ScheduleOfEquityMethodInvestmentsTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="ScheduleOfEquityMethodInvestmentsTable" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to ScheduleOfEquityMethodInvestmentsTable" order="8000.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfEquityMethodInvestmentsTable" xlink:to="AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" xlink:title="definition: ScheduleOfEquityMethodInvestmentsTable to AcquiredFiniteLivedIntangibleAssetsByMajorClassAxis" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetWeightedAverageUsefulLife" xlink:label="AcquiredFiniteLivedIntangibleAssetWeightedAverageUsefulLife" xlink:title="AcquiredFiniteLivedIntangibleAssetWeightedAverageUsefulLife" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="AcquiredFiniteLivedIntangibleAssetWeightedAverageUsefulLife" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to AcquiredFiniteLivedIntangibleAssetWeightedAverageUsefulLife" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AmortizationOfAcquiredIntangibleAssets" xlink:label="AmortizationOfAcquiredIntangibleAssets" xlink:title="AmortizationOfAcquiredIntangibleAssets" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="AmortizationOfAcquiredIntangibleAssets" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to AmortizationOfAcquiredIntangibleAssets" use="optional" order="8002.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FiniteLivedAcquiredIntangibleAssetsFutureAnnualAmortizationExpenseForNextFiveYears" xlink:label="FiniteLivedAcquiredIntangibleAssetsFutureAnnualAmortizationExpenseForNextFiveYears" xlink:title="FiniteLivedAcquiredIntangibleAssetsFutureAnnualAmortizationExpenseForNextFiveYears" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="FiniteLivedAcquiredIntangibleAssetsFutureAnnualAmortizationExpenseForNextFiveYears" xlink:title="definition: ScheduleOfEquityMethodInvestmentsLineItems to FiniteLivedAcquiredIntangibleAssetsFutureAnnualAmortizationExpenseForNextFiveYears" use="optional" order="8003.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureRelatedPartyTransactionsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="RelatedPartyTransactionLineItems" xlink:title="RelatedPartyTransactionLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="RelatedPartyTransactionLineItems" xlink:to="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:title="definition: RelatedPartyTransactionLineItems to ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="RelatedPartyTransactionsByRelatedPartyAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="RelatedPartyTransactionsByRelatedPartyAxis" xlink:title="definition: ScheduleOfRelatedPartyTransactionsByRelatedPartyTable to RelatedPartyTransactionsByRelatedPartyAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain" xlink:title="RelatedPartyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="RelatedPartyDomain_2" xlink:title="RelatedPartyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="RelatedPartyDomain_2" xlink:title="definition: RelatedPartyTransactionsByRelatedPartyAxis to RelatedPartyDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AffiliatedEntityMember" xlink:label="AffiliatedEntityMember" xlink:title="AffiliatedEntityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyDomain" xlink:to="AffiliatedEntityMember" xlink:title="definition: RelatedPartyDomain to AffiliatedEntityMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueFromRelatedParties" xlink:label="DueFromRelatedParties" xlink:title="DueFromRelatedParties" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueFromRelatedParties" xlink:title="definition: RelatedPartyTransactionLineItems to DueFromRelatedParties" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueFromRelatedPartiesCurrent" xlink:label="DueFromRelatedPartiesCurrent" xlink:title="DueFromRelatedPartiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueFromRelatedPartiesCurrent" xlink:title="definition: RelatedPartyTransactionLineItems to DueFromRelatedPartiesCurrent" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueFromRelatedPartiesNoncurrent" xlink:label="DueFromRelatedPartiesNoncurrent" xlink:title="DueFromRelatedPartiesNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueFromRelatedPartiesNoncurrent" xlink:title="definition: RelatedPartyTransactionLineItems to DueFromRelatedPartiesNoncurrent" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent" xlink:label="DueToRelatedPartiesCurrent" xlink:title="DueToRelatedPartiesCurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueToRelatedPartiesCurrent" xlink:title="definition: RelatedPartyTransactionLineItems to DueToRelatedPartiesCurrent" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueToRelatedPartiesNoncurrent" xlink:label="DueToRelatedPartiesNoncurrent" xlink:title="DueToRelatedPartiesNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueToRelatedPartiesNoncurrent" xlink:title="definition: RelatedPartyTransactionLineItems to DueToRelatedPartiesNoncurrent" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DueToRelatedPartiesCurrentAndNoncurrent" xlink:label="DueToRelatedPartiesCurrentAndNoncurrent" xlink:title="DueToRelatedPartiesCurrentAndNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RelatedPartyTransactionLineItems" xlink:to="DueToRelatedPartiesCurrentAndNoncurrent" xlink:title="definition: RelatedPartyTransactionLineItems to DueToRelatedPartiesCurrentAndNoncurrent" use="optional" order="7.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureVariableInterestEntitiesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="VariableInterestEntityLineItems" xlink:title="VariableInterestEntityLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="ScheduleOfVariableInterestEntitiesTable" xlink:title="ScheduleOfVariableInterestEntitiesTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="VariableInterestEntityLineItems" xlink:to="ScheduleOfVariableInterestEntitiesTable" xlink:title="definition: VariableInterestEntityLineItems to ScheduleOfVariableInterestEntitiesTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:title="VariableInterestEntitiesByClassificationOfEntityAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfVariableInterestEntitiesTable" xlink:to="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:title="definition: ScheduleOfVariableInterestEntitiesTable to VariableInterestEntitiesByClassificationOfEntityAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="ClassificationOfVariableInterestEntityDomain" xlink:title="ClassificationOfVariableInterestEntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:to="ClassificationOfVariableInterestEntityDomain" xlink:title="definition: VariableInterestEntitiesByClassificationOfEntityAxis to ClassificationOfVariableInterestEntityDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="ClassificationOfVariableInterestEntityDomain_2" xlink:title="ClassificationOfVariableInterestEntityDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="VariableInterestEntitiesByClassificationOfEntityAxis" xlink:to="ClassificationOfVariableInterestEntityDomain_2" xlink:title="definition: VariableInterestEntitiesByClassificationOfEntityAxis to ClassificationOfVariableInterestEntityDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SponsoredInvestmentFundsMember" xlink:label="SponsoredInvestmentFundsMember" xlink:title="SponsoredInvestmentFundsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassificationOfVariableInterestEntityDomain" xlink:to="SponsoredInvestmentFundsMember" xlink:title="definition: ClassificationOfVariableInterestEntityDomain to SponsoredInvestmentFundsMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_TrustPreferredVehiclesMember" xlink:label="TrustPreferredVehiclesMember" xlink:title="TrustPreferredVehiclesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassificationOfVariableInterestEntityDomain" xlink:to="TrustPreferredVehiclesMember" xlink:title="definition: ClassificationOfVariableInterestEntityDomain to TrustPreferredVehiclesMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet" xlink:label="VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet" xlink:title="VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet" xlink:title="definition: VariableInterestEntityLineItems to VariableInterestEntityNonconsolidatedCarryingAmountAssetsAndLiabilitiesNet" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount" xlink:label="VariableInterestEntityEntityMaximumLossExposureAmount" xlink:title="VariableInterestEntityEntityMaximumLossExposureAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="VariableInterestEntityLineItems" xlink:to="VariableInterestEntityEntityMaximumLossExposureAmount" xlink:title="definition: VariableInterestEntityLineItems to VariableInterestEntityEntityMaximumLossExposureAmount" use="optional" order="3.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureConvertibleSecuritiesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" use="optional" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: DebtInstrumentTable to DebtInstrumentAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="ConvertibleDebtSecuritiesMember" xlink:title="ConvertibleDebtSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="ConvertibleDebtSecuritiesMember" xlink:title="definition: DebtInstrumentNameDomain to ConvertibleDebtSecuritiesMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecuritiesMember" xlink:label="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:title="JuniorConvertibleTrustPreferredSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:title="definition: DebtInstrumentNameDomain to JuniorConvertibleTrustPreferredSecuritiesMember" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecurities2007Member" xlink:label="JuniorConvertibleTrustPreferredSecurities2007Member" xlink:title="JuniorConvertibleTrustPreferredSecurities2007Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:to="JuniorConvertibleTrustPreferredSecurities2007Member" xlink:title="definition: JuniorConvertibleTrustPreferredSecuritiesMember to JuniorConvertibleTrustPreferredSecurities2007Member" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecurities2006Member" xlink:label="JuniorConvertibleTrustPreferredSecurities2006Member" xlink:title="JuniorConvertibleTrustPreferredSecurities2006Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:to="JuniorConvertibleTrustPreferredSecurities2006Member" xlink:title="definition: JuniorConvertibleTrustPreferredSecuritiesMember to JuniorConvertibleTrustPreferredSecurities2006Member" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SeniorConvertibleDebtAbstract" xlink:label="SeniorConvertibleDebtAbstract" xlink:title="SeniorConvertibleDebtAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="SeniorConvertibleDebtAbstract" xlink:title="definition: DebtInstrumentLineItems to SeniorConvertibleDebtAbstract" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SeniorConvertibleDebtNoncurrent" xlink:label="SeniorConvertibleDebtNoncurrent" xlink:title="SeniorConvertibleDebtNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeniorConvertibleDebtAbstract" xlink:to="SeniorConvertibleDebtNoncurrent" xlink:title="definition: SeniorConvertibleDebtAbstract to SeniorConvertibleDebtNoncurrent" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="DebtInstrumentFaceAmount" xlink:title="DebtInstrumentFaceAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeniorConvertibleDebtAbstract" xlink:to="DebtInstrumentFaceAmount" xlink:title="definition: SeniorConvertibleDebtAbstract to DebtInstrumentFaceAmount" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentTerm" xlink:label="DebtInstrumentTerm" xlink:title="DebtInstrumentTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeniorConvertibleDebtAbstract" xlink:to="DebtInstrumentTerm" xlink:title="definition: SeniorConvertibleDebtAbstract to DebtInstrumentTerm" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentInterestRateUsedForAccretionOfCarryingValueToPrincipalMaturity" xlink:label="DebtInstrumentInterestRateUsedForAccretionOfCarryingValueToPrincipalMaturity" xlink:title="DebtInstrumentInterestRateUsedForAccretionOfCarryingValueToPrincipalMaturity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeniorConvertibleDebtAbstract" xlink:to="DebtInstrumentInterestRateUsedForAccretionOfCarryingValueToPrincipalMaturity" xlink:title="definition: SeniorConvertibleDebtAbstract to DebtInstrumentInterestRateUsedForAccretionOfCarryingValueToPrincipalMaturity" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredDebtNoncurrent" xlink:label="JuniorConvertibleTrustPreferredDebtNoncurrent" xlink:title="JuniorConvertibleTrustPreferredDebtNoncurrent" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeniorConvertibleDebtAbstract" xlink:to="JuniorConvertibleTrustPreferredDebtNoncurrent" xlink:title="definition: SeniorConvertibleDebtAbstract to JuniorConvertibleTrustPreferredDebtNoncurrent" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:label="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:title="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ConvertibilityOfDebtDebtPriceTestPercentageOfClosingStockPriceUsedInCalculation" xlink:label="ConvertibilityOfDebtDebtPriceTestPercentageOfClosingStockPriceUsedInCalculation" xlink:title="ConvertibilityOfDebtDebtPriceTestPercentageOfClosingStockPriceUsedInCalculation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="ConvertibilityOfDebtDebtPriceTestPercentageOfClosingStockPriceUsedInCalculation" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to ConvertibilityOfDebtDebtPriceTestPercentageOfClosingStockPriceUsedInCalculation" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ConvertibilityOfDebtStockPriceTestTargetPercentageOfClosingStockPriceToConversionPriceThatMustBeExceeded" xlink:label="ConvertibilityOfDebtStockPriceTestTargetPercentageOfClosingStockPriceToConversionPriceThatMustBeExceeded" xlink:title="ConvertibilityOfDebtStockPriceTestTargetPercentageOfClosingStockPriceToConversionPriceThatMustBeExceeded" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="ConvertibilityOfDebtStockPriceTestTargetPercentageOfClosingStockPriceToConversionPriceThatMustBeExceeded" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to ConvertibilityOfDebtStockPriceTestTargetPercentageOfClosingStockPriceToConversionPriceThatMustBeExceeded" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentPricePerShareThatMustBeExceededForConversion" xlink:label="DebtInstrumentPricePerShareThatMustBeExceededForConversion" xlink:title="DebtInstrumentPricePerShareThatMustBeExceededForConversion" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DebtInstrumentPricePerShareThatMustBeExceededForConversion" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DebtInstrumentPricePerShareThatMustBeExceededForConversion" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DeferredTaxLiabilityFromExcessInterestExpenseCalculation" xlink:label="DeferredTaxLiabilityFromExcessInterestExpenseCalculation" xlink:title="DeferredTaxLiabilityFromExcessInterestExpenseCalculation" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DeferredTaxLiabilityFromExcessInterestExpenseCalculation" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DeferredTaxLiabilityFromExcessInterestExpenseCalculation" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentTaxDeductionRate" xlink:label="DebtInstrumentTaxDeductionRate" xlink:title="DebtInstrumentTaxDeductionRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DebtInstrumentTaxDeductionRate" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DebtInstrumentTaxDeductionRate" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="DebtInstrumentInterestRateStatedPercentage" xlink:title="DebtInstrumentInterestRateStatedPercentage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DebtInstrumentInterestRateStatedPercentage" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DebtInstrumentInterestRateStatedPercentage" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="DebtInstrumentConvertibleConversionPrice1" xlink:title="DebtInstrumentConvertibleConversionPrice1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DebtInstrumentConvertibleConversionPrice1" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DebtInstrumentConvertibleConversionPrice1" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio" xlink:label="DebtInstrumentConvertibleConversionRatio" xlink:title="DebtInstrumentConvertibleConversionRatio" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DebtInstrumentConvertibleConversionRatio" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DebtInstrumentConvertibleConversionRatio" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" xlink:label="DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" xlink:title="DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract" xlink:to="DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" xlink:title="definition: DebtInstrumentPrincipalTermsOfConvertibleDebtAbstract to DebtInstrumentPrincipalAmountDenominationForConversionIntoCommonStock" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentOutstandingNumber" xlink:label="DebtInstrumentOutstandingNumber" xlink:title="DebtInstrumentOutstandingNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentOutstandingNumber" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentOutstandingNumber" use="optional" order="2.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureJuniorConvertibleTrustPreferredSecuritiesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" use="optional" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: DebtInstrumentTable to DebtInstrumentAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecurities2006Member" xlink:label="JuniorConvertibleTrustPreferredSecurities2006Member" xlink:title="JuniorConvertibleTrustPreferredSecurities2006Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="JuniorConvertibleTrustPreferredSecurities2006Member" xlink:title="definition: DebtInstrumentNameDomain to JuniorConvertibleTrustPreferredSecurities2006Member" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecurities2007Member" xlink:label="JuniorConvertibleTrustPreferredSecurities2007Member" xlink:title="JuniorConvertibleTrustPreferredSecurities2007Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="JuniorConvertibleTrustPreferredSecurities2007Member" xlink:title="definition: DebtInstrumentNameDomain to JuniorConvertibleTrustPreferredSecurities2007Member" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentPrincipalTermsOfJuniorConvertibleTrustPreferredSecuritiesAbstract" xlink:label="DebtInstrumentPrincipalTermsOfJuniorConvertibleTrustPreferredSecuritiesAbstract" xlink:title="DebtInstrumentPrincipalTermsOfJuniorConvertibleTrustPreferredSecuritiesAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentPrincipalTermsOfJuniorConvertibleTrustPreferredSecuritiesAbstract" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentPrincipalTermsOfJuniorConvertibleTrustPreferredSecuritiesAbstract" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:label="ProceedsFromIssuanceOfDebt" xlink:title="ProceedsFromIssuanceOfDebt" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ProceedsFromIssuanceOfDebt" xlink:title="definition: DebtInstrumentLineItems to ProceedsFromIssuanceOfDebt" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentDecreaseRepayments" xlink:label="DebtInstrumentDecreaseRepayments" xlink:title="DebtInstrumentDecreaseRepayments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentDecreaseRepayments" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentDecreaseRepayments" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities" xlink:label="ProceedsFromIssuanceOfTrustPreferredSecurities" xlink:title="ProceedsFromIssuanceOfTrustPreferredSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="ProceedsFromIssuanceOfTrustPreferredSecurities" xlink:title="definition: DebtInstrumentLineItems to ProceedsFromIssuanceOfTrustPreferredSecurities" use="optional" order="8.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureSeniorBankDebtDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="DebtInstrumentLineItems" xlink:title="DebtInstrumentLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="DebtInstrumentTable" xlink:title="DebtInstrumentTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTable" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DebtInstrumentTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: DebtInstrumentTable to DebtInstrumentAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_SeniorUnsecuredCreditFacilityMember" xlink:label="SeniorUnsecuredCreditFacilityMember" xlink:title="SeniorUnsecuredCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="SeniorUnsecuredCreditFacilityMember" xlink:title="definition: DebtInstrumentNameDomain to SeniorUnsecuredCreditFacilityMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LineOfCreditMember" xlink:label="LineOfCreditMember" xlink:title="LineOfCreditMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="LineOfCreditMember" xlink:title="definition: DebtInstrumentNameDomain to LineOfCreditMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_UnsecuredTermLoanCreditFacilityMember" xlink:label="UnsecuredTermLoanCreditFacilityMember" xlink:title="UnsecuredTermLoanCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="UnsecuredTermLoanCreditFacilityMember" xlink:title="definition: DebtInstrumentNameDomain to UnsecuredTermLoanCreditFacilityMember" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_PreviousCreditFacilityMember" xlink:label="PreviousCreditFacilityMember" xlink:title="PreviousCreditFacilityMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="PreviousCreditFacilityMember" xlink:title="definition: DebtInstrumentNameDomain to PreviousCreditFacilityMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="LineOfCreditFacilityMaximumBorrowingCapacity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityMaximumBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityMaximumBorrowingCapacity" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DebtInstrumentTerm" xlink:label="DebtInstrumentTerm" xlink:title="DebtInstrumentTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="DebtInstrumentTerm" xlink:title="definition: DebtInstrumentLineItems to DebtInstrumentTerm" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" xlink:label="LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" xlink:title="LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityIncreaseInMaximumBorrowingCapacity" use="optional" order="8.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity" xlink:label="LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity" xlink:title="LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity" xlink:title="definition: DebtInstrumentLineItems to LineOfCreditFacilityOptionToIncreaseMaximumBorrowingCapacity" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2016" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2016" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2016" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2016" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2016" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2015" xlink:label="LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2015" xlink:title="LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2015" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2015" xlink:title="definition: DebtInstrumentLineItems to LongTermDebtMaturitiesRepaymentsOfPrincipalInYear2015" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RepaymentsOfLongTermLinesOfCredit" xlink:label="RepaymentsOfLongTermLinesOfCredit" xlink:title="RepaymentsOfLongTermLinesOfCredit" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentLineItems" xlink:to="RepaymentsOfLongTermLinesOfCredit" xlink:title="definition: DebtInstrumentLineItems to RepaymentsOfLongTermLinesOfCredit" use="optional" order="7.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureFinancialInstrumentsAndRiskManagementDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="DebtInstrumentAxis" xlink:title="DebtInstrumentAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain" xlink:title="DebtInstrumentNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="DebtInstrumentNameDomain_2" xlink:title="DebtInstrumentNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DebtInstrumentAxis" xlink:to="DebtInstrumentNameDomain_2" xlink:title="definition: DebtInstrumentAxis to DebtInstrumentNameDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="ConvertibleDebtSecuritiesMember" xlink:title="ConvertibleDebtSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="ConvertibleDebtSecuritiesMember" xlink:title="definition: DebtInstrumentNameDomain to ConvertibleDebtSecuritiesMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecuritiesMember" xlink:label="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:title="JuniorConvertibleTrustPreferredSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DebtInstrumentNameDomain" xlink:to="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:title="definition: DebtInstrumentNameDomain to JuniorConvertibleTrustPreferredSecuritiesMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:title="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="FairValueByBalanceSheetGroupingTable" xlink:title="FairValueByBalanceSheetGroupingTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="FairValueByBalanceSheetGroupingTable" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to FairValueByBalanceSheetGroupingTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueByBalanceSheetGroupingTable" xlink:to="DebtInstrumentAxis" xlink:title="definition: FairValueByBalanceSheetGroupingTable to DebtInstrumentAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="DebtInstrumentFairValue" xlink:title="DebtInstrumentFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="DebtInstrumentFairValue" xlink:title="definition: FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems to DebtInstrumentFairValue" use="optional" order="2.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureDerivativeFinancialInstrumentsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeLineItems" xlink:label="DerivativeLineItems" xlink:title="DerivativeLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeTable" xlink:label="DerivativeTable" xlink:title="DerivativeTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DerivativeLineItems" xlink:to="DerivativeTable" xlink:title="definition: DerivativeLineItems to DerivativeTable" use="optional" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="DerivativeInstrumentRiskAxis" xlink:title="DerivativeInstrumentRiskAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeTable" xlink:to="DerivativeInstrumentRiskAxis" xlink:title="definition: DerivativeTable to DerivativeInstrumentRiskAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="DerivativeContractTypeDomain" xlink:title="DerivativeContractTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentRiskAxis" xlink:to="DerivativeContractTypeDomain" xlink:title="definition: DerivativeInstrumentRiskAxis to DerivativeContractTypeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="DerivativeContractTypeDomain_2" xlink:title="DerivativeContractTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentRiskAxis" xlink:to="DerivativeContractTypeDomain_2" xlink:title="definition: DerivativeInstrumentRiskAxis to DerivativeContractTypeDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="InterestRateSwapMember" xlink:title="InterestRateSwapMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="InterestRateSwapMember" xlink:title="definition: DerivativeContractTypeDomain to InterestRateSwapMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_TreasuryRateLockMember" xlink:label="TreasuryRateLockMember" xlink:title="TreasuryRateLockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="TreasuryRateLockMember" xlink:title="definition: DerivativeContractTypeDomain to TreasuryRateLockMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeByNatureAxis" xlink:label="DerivativeByNatureAxis" xlink:title="DerivativeByNatureAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeTable" xlink:to="DerivativeByNatureAxis" xlink:title="definition: DerivativeTable to DerivativeByNatureAxis" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeNameDomain" xlink:label="DerivativeNameDomain" xlink:title="DerivativeNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeByNatureAxis" xlink:to="DerivativeNameDomain" xlink:title="definition: DerivativeByNatureAxis to DerivativeNameDomain" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeNameDomain" xlink:label="DerivativeNameDomain_2" xlink:title="DerivativeNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeByNatureAxis" xlink:to="DerivativeNameDomain_2" xlink:title="definition: DerivativeByNatureAxis to DerivativeNameDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CounterpartyAPaying1.67PercentInterestMember" xlink:label="CounterpartyAPaying1.67PercentInterestMember" xlink:title="CounterpartyAPaying1.67PercentInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="CounterpartyAPaying1.67PercentInterestMember" xlink:title="definition: DerivativeNameDomain to CounterpartyAPaying1.67PercentInterestMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CounterpartyAPaying1.65PercentInterestMember" xlink:label="CounterpartyAPaying1.65PercentInterestMember" xlink:title="CounterpartyAPaying1.65PercentInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="CounterpartyAPaying1.65PercentInterestMember" xlink:title="definition: DerivativeNameDomain to CounterpartyAPaying1.65PercentInterestMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CounterpartyBPaying1.59PercentInterestMember" xlink:label="CounterpartyBPaying1.59PercentInterestMember" xlink:title="CounterpartyBPaying1.59PercentInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="CounterpartyBPaying1.59PercentInterestMember" xlink:title="definition: DerivativeNameDomain to CounterpartyBPaying1.59PercentInterestMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CounterpartyBPaying2.14PercentInterestMember" xlink:label="CounterpartyBPaying2.14PercentInterestMember" xlink:title="CounterpartyBPaying2.14PercentInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="CounterpartyBPaying2.14PercentInterestMember" xlink:title="definition: DerivativeNameDomain to CounterpartyBPaying2.14PercentInterestMember" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CounterpartyAPaying2.94PercentInterestMember" xlink:label="CounterpartyAPaying2.94PercentInterestMember" xlink:title="CounterpartyAPaying2.94PercentInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="CounterpartyAPaying2.94PercentInterestMember" xlink:title="definition: DerivativeNameDomain to CounterpartyAPaying2.94PercentInterestMember" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_CounterpartyBPaying2.89PercentInterestMember" xlink:label="CounterpartyBPaying2.89PercentInterestMember" xlink:title="CounterpartyBPaying2.89PercentInterestMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeNameDomain" xlink:to="CounterpartyBPaying2.89PercentInterestMember" xlink:title="definition: DerivativeNameDomain to CounterpartyBPaying2.89PercentInterestMember" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NotionalAmountOfInterestRateDerivatives" xlink:label="NotionalAmountOfInterestRateDerivatives" xlink:title="NotionalAmountOfInterestRateDerivatives" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="NotionalAmountOfInterestRateDerivatives" xlink:title="definition: DerivativeLineItems to NotionalAmountOfInterestRateDerivatives" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CollateralAlreadyPostedAggregateFairValue" xlink:label="CollateralAlreadyPostedAggregateFairValue" xlink:title="CollateralAlreadyPostedAggregateFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="CollateralAlreadyPostedAggregateFairValue" xlink:title="definition: DerivativeLineItems to CollateralAlreadyPostedAggregateFairValue" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnrealizedGainLossOnCashFlowHedgingInstruments" xlink:label="UnrealizedGainLossOnCashFlowHedgingInstruments" xlink:title="UnrealizedGainLossOnCashFlowHedgingInstruments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="UnrealizedGainLossOnCashFlowHedgingInstruments" xlink:title="definition: DerivativeLineItems to UnrealizedGainLossOnCashFlowHedgingInstruments" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeDescriptionOfVariableRateBasis" xlink:label="DerivativeDescriptionOfVariableRateBasis" xlink:title="DerivativeDescriptionOfVariableRateBasis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="DerivativeDescriptionOfVariableRateBasis" xlink:title="definition: DerivativeLineItems to DerivativeDescriptionOfVariableRateBasis" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeFixedInterestRate" xlink:label="DerivativeFixedInterestRate" xlink:title="DerivativeFixedInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="DerivativeFixedInterestRate" xlink:title="definition: DerivativeLineItems to DerivativeFixedInterestRate" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_DerivativeFixedInterestRateOnRemainingNotionalAmount" xlink:label="DerivativeFixedInterestRateOnRemainingNotionalAmount" xlink:title="DerivativeFixedInterestRateOnRemainingNotionalAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="DerivativeFixedInterestRateOnRemainingNotionalAmount" xlink:title="definition: DerivativeLineItems to DerivativeFixedInterestRateOnRemainingNotionalAmount" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_RemainingNotionalAmountOfInterestRateDerivatives" xlink:label="RemainingNotionalAmountOfInterestRateDerivatives" xlink:title="RemainingNotionalAmountOfInterestRateDerivatives" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="RemainingNotionalAmountOfInterestRateDerivatives" xlink:title="definition: DerivativeLineItems to RemainingNotionalAmountOfInterestRateDerivatives" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:label="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:title="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeLineItems" xlink:to="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:title="definition: DerivativeLineItems to DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" use="optional" order="5.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureDerivativeFinancialInstrumentsDetails2">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="DerivativeInstrumentRiskAxis" xlink:title="DerivativeInstrumentRiskAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="DerivativeContractTypeDomain" xlink:title="DerivativeContractTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentRiskAxis" xlink:to="DerivativeContractTypeDomain" xlink:title="definition: DerivativeInstrumentRiskAxis to DerivativeContractTypeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="InterestRateSwapMember" xlink:title="InterestRateSwapMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="InterestRateSwapMember" xlink:title="definition: DerivativeContractTypeDomain to InterestRateSwapMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_TreasuryRateLockMember" xlink:label="TreasuryRateLockMember" xlink:title="TreasuryRateLockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="TreasuryRateLockMember" xlink:title="definition: DerivativeContractTypeDomain to TreasuryRateLockMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="DerivativeInstrumentsGainLossLineItems" xlink:title="DerivativeInstrumentsGainLossLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:label="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:title="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DerivativeInstrumentsGainLossLineItems" xlink:to="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:title="definition: DerivativeInstrumentsGainLossLineItems to DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:label="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable to DerivativeInstrumentsGainLossByHedgingRelationshipAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain" xlink:title="HedgingRelationshipDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_HedgingRelationshipDomain" xlink:label="HedgingRelationshipDomain_2" xlink:title="HedgingRelationshipDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipAxis" xlink:to="HedgingRelationshipDomain_2" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipAxis to HedgingRelationshipDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashFlowHedgingMember" xlink:label="CashFlowHedgingMember" xlink:title="CashFlowHedgingMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="HedgingRelationshipDomain" xlink:to="CashFlowHedgingMember" xlink:title="definition: HedgingRelationshipDomain to CashFlowHedgingMember" use="optional" order="1.0" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="DerivativeInstrumentRiskAxis" xlink:title="definition: DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable to DerivativeInstrumentRiskAxis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:label="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:title="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeInstrumentsGainLossLineItems" xlink:to="DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" xlink:title="definition: DerivativeInstrumentsGainLossLineItems to DerivativeInstrumentsGainLossRecognizedInOtherComprehensiveIncomeEffectivePortionNet" use="optional" order="2.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureDerivativeFinancialInstrumentsDetails3">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeInstrumentRiskAxis" xlink:label="DerivativeInstrumentRiskAxis" xlink:title="DerivativeInstrumentRiskAxis" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeContractTypeDomain" xlink:label="DerivativeContractTypeDomain" xlink:title="DerivativeContractTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="DerivativeInstrumentRiskAxis" xlink:to="DerivativeContractTypeDomain" xlink:title="definition: DerivativeInstrumentRiskAxis to DerivativeContractTypeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="InterestRateSwapMember" xlink:title="InterestRateSwapMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="InterestRateSwapMember" xlink:title="definition: DerivativeContractTypeDomain to InterestRateSwapMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_TreasuryRateLockMember" xlink:label="TreasuryRateLockMember" xlink:title="TreasuryRateLockMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativeContractTypeDomain" xlink:to="TreasuryRateLockMember" xlink:title="definition: DerivativeContractTypeDomain to TreasuryRateLockMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativesFairValueLineItems" xlink:label="DerivativesFairValueLineItems" xlink:title="DerivativesFairValueLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:title="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DerivativesFairValueLineItems" xlink:to="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:title="definition: DerivativesFairValueLineItems to FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="DerivativeInstrumentRiskAxis" xlink:title="definition: FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable to DerivativeInstrumentRiskAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestRateCashFlowHedgeAssetAtFairValue" xlink:label="InterestRateCashFlowHedgeAssetAtFairValue" xlink:title="InterestRateCashFlowHedgeAssetAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DerivativesFairValueLineItems" xlink:to="InterestRateCashFlowHedgeAssetAtFairValue" xlink:title="definition: DerivativesFairValueLineItems to InterestRateCashFlowHedgeAssetAtFairValue" use="optional" order="2.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureFairValueMeasurementsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="FairValueByMeasurementFrequencyAxis" xlink:title="FairValueByMeasurementFrequencyAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByMeasurementFrequencyAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByMeasurementFrequencyAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain" xlink:title="FairValueMeasurementFrequencyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="FairValueMeasurementFrequencyDomain_2" xlink:title="FairValueMeasurementFrequencyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByMeasurementFrequencyAxis" xlink:to="FairValueMeasurementFrequencyDomain_2" xlink:title="definition: FairValueByMeasurementFrequencyAxis to FairValueMeasurementFrequencyDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="FairValueMeasurementsRecurringMember" xlink:title="FairValueMeasurementsRecurringMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementFrequencyDomain" xlink:to="FairValueMeasurementsRecurringMember" xlink:title="definition: FairValueMeasurementFrequencyDomain to FairValueMeasurementsRecurringMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="FairValueByFairValueHierarchyLevelAxis" xlink:title="FairValueByFairValueHierarchyLevelAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="FairValueByFairValueHierarchyLevelAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable to FairValueByFairValueHierarchyLevelAxis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="FairValueMeasurementsFairValueHierarchyDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByFairValueHierarchyLevelAxis" xlink:to="FairValueMeasurementsFairValueHierarchyDomain_2" xlink:title="definition: FairValueByFairValueHierarchyLevelAxis to FairValueMeasurementsFairValueHierarchyDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="EstimateOfFairValueFairValueDisclosureMember" xlink:title="EstimateOfFairValueFairValueDisclosureMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="EstimateOfFairValueFairValueDisclosureMember" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to EstimateOfFairValueFairValueDisclosureMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="FairValueInputsLevel1Member" xlink:title="FairValueInputsLevel1Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel1Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel1Member" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="FairValueInputsLevel2Member" xlink:title="FairValueInputsLevel2Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel2Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel2Member" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="FairValueInputsLevel3Member" xlink:title="FairValueInputsLevel3Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueMeasurementsFairValueHierarchyDomain" xlink:to="FairValueInputsLevel3Member" xlink:title="definition: FairValueMeasurementsFairValueHierarchyDomain to FairValueInputsLevel3Member" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="AssetsFairValueDisclosureAbstract" xlink:title="AssetsFairValueDisclosureAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="AssetsFairValueDisclosureAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to AssetsFairValueDisclosureAbstract" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="CashAndCashEquivalentsFairValueDisclosure" xlink:title="CashAndCashEquivalentsFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsFairValueDisclosureAbstract" xlink:to="CashAndCashEquivalentsFairValueDisclosure" xlink:title="definition: AssetsFairValueDisclosureAbstract to CashAndCashEquivalentsFairValueDisclosure" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_InvestmentsInPartnerships" xlink:label="InvestmentsInPartnerships" xlink:title="InvestmentsInPartnerships" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsFairValueDisclosureAbstract" xlink:to="InvestmentsInPartnerships" xlink:title="definition: AssetsFairValueDisclosureAbstract to InvestmentsInPartnerships" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TradingSecuritiesFairValueDisclosure" xlink:label="TradingSecuritiesFairValueDisclosure" xlink:title="TradingSecuritiesFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsFairValueDisclosureAbstract" xlink:to="TradingSecuritiesFairValueDisclosure" xlink:title="definition: AssetsFairValueDisclosureAbstract to TradingSecuritiesFairValueDisclosure" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesFairValueDisclosure" xlink:label="AvailableForSaleSecuritiesFairValueDisclosure" xlink:title="AvailableForSaleSecuritiesFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsFairValueDisclosureAbstract" xlink:to="AvailableForSaleSecuritiesFairValueDisclosure" xlink:title="definition: AssetsFairValueDisclosureAbstract to AvailableForSaleSecuritiesFairValueDisclosure" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestRateDerivativeAssetsAtFairValue" xlink:label="InterestRateDerivativeAssetsAtFairValue" xlink:title="InterestRateDerivativeAssetsAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsFairValueDisclosureAbstract" xlink:to="InterestRateDerivativeAssetsAtFairValue" xlink:title="definition: AssetsFairValueDisclosureAbstract to InterestRateDerivativeAssetsAtFairValue" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AlternativeInvestmentsFairValueDisclosure" xlink:label="AlternativeInvestmentsFairValueDisclosure" xlink:title="AlternativeInvestmentsFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AssetsFairValueDisclosureAbstract" xlink:to="AlternativeInvestmentsFairValueDisclosure" xlink:title="definition: AssetsFairValueDisclosureAbstract to AlternativeInvestmentsFairValueDisclosure" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="LiabilitiesFairValueDisclosureAbstract" xlink:title="LiabilitiesFairValueDisclosureAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="LiabilitiesFairValueDisclosureAbstract" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems to LiabilitiesFairValueDisclosureAbstract" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisObligations" xlink:label="FairValueLiabilitiesMeasuredOnRecurringBasisObligations" xlink:title="FairValueLiabilitiesMeasuredOnRecurringBasisObligations" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesFairValueDisclosureAbstract" xlink:to="FairValueLiabilitiesMeasuredOnRecurringBasisObligations" xlink:title="definition: LiabilitiesFairValueDisclosureAbstract to FairValueLiabilitiesMeasuredOnRecurringBasisObligations" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RelatedPartyTransactionDueFromToRelatedParty" xlink:label="RelatedPartyTransactionDueFromToRelatedParty" xlink:title="RelatedPartyTransactionDueFromToRelatedParty" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesFairValueDisclosureAbstract" xlink:to="RelatedPartyTransactionDueFromToRelatedParty" xlink:title="definition: LiabilitiesFairValueDisclosureAbstract to RelatedPartyTransactionDueFromToRelatedParty" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestRateDerivativeLiabilitiesAtFairValue" xlink:label="InterestRateDerivativeLiabilitiesAtFairValue" xlink:title="InterestRateDerivativeLiabilitiesAtFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesFairValueDisclosureAbstract" xlink:to="InterestRateDerivativeLiabilitiesAtFairValue" xlink:title="definition: LiabilitiesFairValueDisclosureAbstract to InterestRateDerivativeLiabilitiesAtFairValue" order="3.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureFairValueMeasurementsDetails3">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:label="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:title="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable" xlink:label="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable" xlink:title="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:to="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems to FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="InvestmentTypeAxis" xlink:title="InvestmentTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable" xlink:to="InvestmentTypeAxis" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareTable to InvestmentTypeAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="InvestmentTypeCategorizationMember" xlink:title="InvestmentTypeCategorizationMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="InvestmentTypeAxis" xlink:to="InvestmentTypeCategorizationMember" xlink:title="definition: InvestmentTypeAxis to InvestmentTypeCategorizationMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="InvestmentTypeCategorizationMember_2" xlink:title="InvestmentTypeCategorizationMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="InvestmentTypeAxis" xlink:to="InvestmentTypeCategorizationMember_2" xlink:title="definition: InvestmentTypeAxis to InvestmentTypeCategorizationMember" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PrivateEquityFundsMember" xlink:label="PrivateEquityFundsMember" xlink:title="PrivateEquityFundsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentTypeCategorizationMember" xlink:to="PrivateEquityFundsMember" xlink:title="definition: InvestmentTypeCategorizationMember to PrivateEquityFundsMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_PrivateFundsMember" xlink:label="PrivateFundsMember" xlink:title="PrivateFundsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentTypeCategorizationMember" xlink:to="PrivateFundsMember" xlink:title="definition: InvestmentTypeCategorizationMember to PrivateFundsMember" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_OtherFundsMember" xlink:label="OtherFundsMember" xlink:title="OtherFundsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="InvestmentTypeCategorizationMember" xlink:to="OtherFundsMember" xlink:title="definition: InvestmentTypeCategorizationMember to OtherFundsMember" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AlternativeInvestmentsFairValueDisclosure" xlink:label="AlternativeInvestmentsFairValueDisclosure" xlink:title="AlternativeInvestmentsFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:to="AlternativeInvestmentsFairValueDisclosure" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems to AlternativeInvestmentsFairValueDisclosure" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments" xlink:label="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments" xlink:title="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:to="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems to FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod" xlink:label="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod" xlink:title="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:to="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems to FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_NotesPayableFairValueSeniorConvertibleNotes" xlink:label="NotesPayableFairValueSeniorConvertibleNotes" xlink:title="NotesPayableFairValueSeniorConvertibleNotes" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:to="NotesPayableFairValueSeniorConvertibleNotes" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems to NotesPayableFairValueSeniorConvertibleNotes" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ConvertibleTrustPreferredSecuritiesFairValueDisclosure" xlink:label="ConvertibleTrustPreferredSecuritiesFairValueDisclosure" xlink:title="ConvertibleTrustPreferredSecuritiesFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems" xlink:to="ConvertibleTrustPreferredSecuritiesFairValueDisclosure" xlink:title="definition: FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLineItems to ConvertibleTrustPreferredSecuritiesFairValueDisclosure" use="optional" order="6.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureFairValueMeasurementsDetails2">
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueByAssetAndLiabilityClassAxis" xlink:label="FairValueByAssetAndLiabilityClassAxis" xlink:title="FairValueByAssetAndLiabilityClassAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="FairValueByAssetAndLiabilityClassAxis" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable to FairValueByAssetAndLiabilityClassAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="FairValueByAssetAndLiabilityClassAxis" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:title="definition: FairValueByAssetAndLiabilityClassAxis to FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="FairValueByAssetAndLiabilityClassAxis" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2" xlink:title="definition: FairValueByAssetAndLiabilityClassAxis to FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ContingentPaymentArrangementsMember" xlink:label="ContingentPaymentArrangementsMember" xlink:title="ContingentPaymentArrangementsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="ContingentPaymentArrangementsMember" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain to ContingentPaymentArrangementsMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ObligationsToRelatedPartiesMember" xlink:label="ObligationsToRelatedPartiesMember" xlink:title="ObligationsToRelatedPartiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="ObligationsToRelatedPartiesMember" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain to ObligationsToRelatedPartiesMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherInvestmentsMember" xlink:label="OtherInvestmentsMember" xlink:title="OtherInvestmentsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:to="OtherInvestmentsMember" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain to OtherInvestmentsMember" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:title="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems to FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesRealizedGainLossIncludedInEarnings" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesRealizedGainLossIncludedInEarnings" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesRealizedGainLossIncludedInEarnings" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesRealizedGainLossIncludedInEarnings" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesRealizedGainLossIncludedInEarnings" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisUnrealizedAssetAndLiabilitiesGainLossIncludedInEarnings" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisUnrealizedAssetAndLiabilitiesGainLossIncludedInEarnings" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisUnrealizedAssetAndLiabilitiesGainLossIncludedInEarnings" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisUnrealizedAssetAndLiabilitiesGainLossIncludedInEarnings" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisUnrealizedAssetAndLiabilitiesGainLossIncludedInEarnings" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesPurchasesSalesIssuancesSettlements" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesPurchasesSalesIssuancesSettlements" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesPurchasesSalesIssuancesSettlements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesPurchasesSalesIssuancesSettlements" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesPurchasesSalesIssuancesSettlements" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesSettlementsAndReductions" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesSettlementsAndReductions" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesSettlementsAndReductions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesSettlementsAndReductions" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetsAndLiabilitiesSettlementsAndReductions" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesTransfersNet" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesTransfersNet" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesTransfersNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesTransfersNet" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesTransfersNet" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesValue" xlink:label="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesValue" xlink:title="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesValue" xlink:title="definition: FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward to FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetAndLiabilitiesValue" use="optional" order="6.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureForwardEquitySaleAgreementsDetails">
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardContractLineItems" xlink:label="ForwardContractLineItems" xlink:title="ForwardContractLineItems" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardContractTable" xlink:label="ForwardContractTable" xlink:title="ForwardContractTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ForwardContractLineItems" xlink:to="ForwardContractTable" xlink:title="definition: ForwardContractLineItems to ForwardContractTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardContractAxis" xlink:label="ForwardContractAxis" xlink:title="ForwardContractAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ForwardContractTable" xlink:to="ForwardContractAxis" xlink:title="definition: ForwardContractTable to ForwardContractAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardContractDomain" xlink:label="ForwardContractDomain" xlink:title="ForwardContractDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ForwardContractAxis" xlink:to="ForwardContractDomain" xlink:title="definition: ForwardContractAxis to ForwardContractDomain" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardContractDomain" xlink:label="ForwardContractDomain_2" xlink:title="ForwardContractDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ForwardContractAxis" xlink:to="ForwardContractDomain_2" xlink:title="definition: ForwardContractAxis to ForwardContractDomain" use="optional" priority="1" order="8001.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EquityForwardMay2008Member" xlink:label="EquityForwardMay2008Member" xlink:title="EquityForwardMay2008Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractDomain" xlink:to="EquityForwardMay2008Member" xlink:title="definition: ForwardContractDomain to EquityForwardMay2008Member" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EquityForwardJuly2009Member" xlink:label="EquityForwardJuly2009Member" xlink:title="EquityForwardJuly2009Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractDomain" xlink:to="EquityForwardJuly2009Member" xlink:title="definition: ForwardContractDomain to EquityForwardJuly2009Member" use="optional" order="8001.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EquityForwardMay2009Member" xlink:label="EquityForwardMay2009Member" xlink:title="EquityForwardMay2009Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractDomain" xlink:to="EquityForwardMay2009Member" xlink:title="definition: ForwardContractDomain to EquityForwardMay2009Member" use="optional" order="8002.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EquityForwardJuly2011FirstMember" xlink:label="EquityForwardJuly2011FirstMember" xlink:title="EquityForwardJuly2011FirstMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractDomain" xlink:to="EquityForwardJuly2011FirstMember" xlink:title="definition: ForwardContractDomain to EquityForwardJuly2011FirstMember" use="optional" order="8003.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EquityForwardJuly2011SecondMember" xlink:label="EquityForwardJuly2011SecondMember" xlink:title="EquityForwardJuly2011SecondMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractDomain" xlink:to="EquityForwardJuly2011SecondMember" xlink:title="definition: ForwardContractDomain to EquityForwardJuly2011SecondMember" use="optional" order="8004.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsNumberOfAgreements" xlink:label="ForwardEquityContractsNumberOfAgreements" xlink:title="ForwardEquityContractsNumberOfAgreements" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractLineItems" xlink:to="ForwardEquityContractsNumberOfAgreements" xlink:title="definition: ForwardContractLineItems to ForwardEquityContractsNumberOfAgreements" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsMaximumValuePerAgreement" xlink:label="ForwardEquityContractsMaximumValuePerAgreement" xlink:title="ForwardEquityContractsMaximumValuePerAgreement" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractLineItems" xlink:to="ForwardEquityContractsMaximumValuePerAgreement" xlink:title="definition: ForwardContractLineItems to ForwardEquityContractsMaximumValuePerAgreement" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquitySaleAgreementsAbstract" xlink:label="ForwardEquitySaleAgreementsAbstract" xlink:title="ForwardEquitySaleAgreementsAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractLineItems" xlink:to="ForwardEquitySaleAgreementsAbstract" xlink:title="definition: ForwardContractLineItems to ForwardEquitySaleAgreementsAbstract" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsSharesSoldAmount" xlink:label="ForwardEquityContractsSharesSoldAmount" xlink:title="ForwardEquityContractsSharesSoldAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardEquitySaleAgreementsAbstract" xlink:to="ForwardEquityContractsSharesSoldAmount" xlink:title="definition: ForwardEquitySaleAgreementsAbstract to ForwardEquityContractsSharesSoldAmount" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsSharesSettledAmount" xlink:label="ForwardEquityContractsSharesSettledAmount" xlink:title="ForwardEquityContractsSharesSettledAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardEquitySaleAgreementsAbstract" xlink:to="ForwardEquityContractsSharesSettledAmount" xlink:title="definition: ForwardEquitySaleAgreementsAbstract to ForwardEquityContractsSharesSettledAmount" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsSharesUnsettledAmount" xlink:label="ForwardEquityContractsSharesUnsettledAmount" xlink:title="ForwardEquityContractsSharesUnsettledAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardEquitySaleAgreementsAbstract" xlink:to="ForwardEquityContractsSharesUnsettledAmount" xlink:title="definition: ForwardEquitySaleAgreementsAbstract to ForwardEquityContractsSharesUnsettledAmount" use="optional" order="8000.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsCommonStockSharesIssued" xlink:label="ForwardEquityContractsCommonStockSharesIssued" xlink:title="ForwardEquityContractsCommonStockSharesIssued" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardEquitySaleAgreementsAbstract" xlink:to="ForwardEquityContractsCommonStockSharesIssued" xlink:title="definition: ForwardEquitySaleAgreementsAbstract to ForwardEquityContractsCommonStockSharesIssued" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ForwardEquityContractsRemainingAvailableStockSales" xlink:label="ForwardEquityContractsRemainingAvailableStockSales" xlink:title="ForwardEquityContractsRemainingAvailableStockSales" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ForwardContractLineItems" xlink:to="ForwardEquityContractsRemainingAvailableStockSales" xlink:title="definition: ForwardContractLineItems to ForwardEquityContractsRemainingAvailableStockSales" use="optional" order="8000.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureEarningsPerShareDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:label="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:title="definition: ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="AntidilutiveSecuritiesNameDomain_2" xlink:title="AntidilutiveSecuritiesNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="AntidilutiveSecuritiesNameDomain_2" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis to AntidilutiveSecuritiesNameDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="StockOptionsMember" xlink:title="StockOptionsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="StockOptionsMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to StockOptionsMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ConvertibleDebtSecuritiesMember" xlink:label="ConvertibleDebtSecuritiesMember" xlink:title="ConvertibleDebtSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="ConvertibleDebtSecuritiesMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to ConvertibleDebtSecuritiesMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_JuniorConvertibleTrustPreferredSecuritiesMember" xlink:label="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:title="JuniorConvertibleTrustPreferredSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesNameDomain" xlink:to="JuniorConvertibleTrustPreferredSecuritiesMember" xlink:title="definition: AntidilutiveSecuritiesNameDomain to JuniorConvertibleTrustPreferredSecuritiesMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems" xlink:to="AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:title="definition: AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems to AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" use="optional" order="2.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureBusinessAndSummaryOfSignificantAccountingPoliciesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain_2" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BuildingMember" xlink:label="BuildingMember" xlink:title="BuildingMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="BuildingMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to BuildingMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_OfficeEquipmentAndFurnitureAndFixturesMember" xlink:label="OfficeEquipmentAndFurnitureAndFixturesMember" xlink:title="OfficeEquipmentAndFurnitureAndFixturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="OfficeEquipmentAndFurnitureAndFixturesMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to OfficeEquipmentAndFurnitureAndFixturesMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:label="SoftwareAndSoftwareDevelopmentCostsMember" xlink:title="SoftwareAndSoftwareDevelopmentCostsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="SoftwareAndSoftwareDevelopmentCostsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to SoftwareAndSoftwareDevelopmentCostsMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLifeMinimum" xlink:label="PropertyPlantAndEquipmentUsefulLifeMinimum" xlink:title="PropertyPlantAndEquipmentUsefulLifeMinimum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLifeMinimum" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLifeMinimum" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLifeMaximum" xlink:label="PropertyPlantAndEquipmentUsefulLifeMaximum" xlink:title="PropertyPlantAndEquipmentUsefulLifeMaximum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLifeMaximum" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLifeMaximum" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLifeAverage" xlink:label="PropertyPlantAndEquipmentUsefulLifeAverage" xlink:title="PropertyPlantAndEquipmentUsefulLifeAverage" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentUsefulLifeAverage" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentUsefulLifeAverage" use="optional" order="4.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureFixedAssetsAndLeaseCommitmentsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="PropertyPlantAndEquipmentLineItems" xlink:title="PropertyPlantAndEquipmentLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="ScheduleOfPropertyPlantAndEquipmentTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="ScheduleOfPropertyPlantAndEquipmentTable" xlink:title="definition: PropertyPlantAndEquipmentLineItems to ScheduleOfPropertyPlantAndEquipmentTable" use="optional" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="PropertyPlantAndEquipmentByTypeAxis" xlink:title="PropertyPlantAndEquipmentByTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="PropertyPlantAndEquipmentByTypeAxis" xlink:title="definition: ScheduleOfPropertyPlantAndEquipmentTable to PropertyPlantAndEquipmentByTypeAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="PropertyPlantAndEquipmentTypeDomain" xlink:title="PropertyPlantAndEquipmentTypeDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PropertyPlantAndEquipmentByTypeAxis" xlink:to="PropertyPlantAndEquipmentTypeDomain" xlink:title="definition: PropertyPlantAndEquipmentByTypeAxis to PropertyPlantAndEquipmentTypeDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:label="SoftwareAndSoftwareDevelopmentCostsMember" xlink:title="SoftwareAndSoftwareDevelopmentCostsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="SoftwareAndSoftwareDevelopmentCostsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to SoftwareAndSoftwareDevelopmentCostsMember" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OfficeEquipmentMember" xlink:label="OfficeEquipmentMember" xlink:title="OfficeEquipmentMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="OfficeEquipmentMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to OfficeEquipmentMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="FurnitureAndFixturesMember" xlink:title="FurnitureAndFixturesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="FurnitureAndFixturesMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to FurnitureAndFixturesMember" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_BuildingAndLeaseholdImprovementsMember" xlink:label="BuildingAndLeaseholdImprovementsMember" xlink:title="BuildingAndLeaseholdImprovementsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="BuildingAndLeaseholdImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to BuildingAndLeaseholdImprovementsMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LandAndLandImprovementsMember" xlink:label="LandAndLandImprovementsMember" xlink:title="LandAndLandImprovementsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentTypeDomain" xlink:to="LandAndLandImprovementsMember" xlink:title="definition: PropertyPlantAndEquipmentTypeDomain to LandAndLandImprovementsMember" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="PropertyPlantAndEquipmentGross" xlink:title="PropertyPlantAndEquipmentGross" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentGross" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentGross" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:title="definition: PropertyPlantAndEquipmentLineItems to AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="PropertyPlantAndEquipmentNet" xlink:title="PropertyPlantAndEquipmentNet" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentNet" xlink:title="definition: PropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentNet" use="optional" order="4.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureStockholdersEquityDetails2">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:label="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:title="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EmployeeStockOptionAndIncentivePlan1997Member" xlink:label="EmployeeStockOptionAndIncentivePlan1997Member" xlink:title="EmployeeStockOptionAndIncentivePlan1997Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionAndIncentivePlan1997Member" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionAndIncentivePlan1997Member" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EmployeeStockOptionAndIncentivePlan2002Member" xlink:label="EmployeeStockOptionAndIncentivePlan2002Member" xlink:title="EmployeeStockOptionAndIncentivePlan2002Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionAndIncentivePlan2002Member" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionAndIncentivePlan2002Member" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EmployeeStockOptionAndIncentivePlan2006Member" xlink:label="EmployeeStockOptionAndIncentivePlan2006Member" xlink:title="EmployeeStockOptionAndIncentivePlan2006Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionAndIncentivePlan2006Member" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionAndIncentivePlan2006Member" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_LongTermExecutiveIncentiveAndDeferredCompensationPlanMember" xlink:label="LongTermExecutiveIncentiveAndDeferredCompensationPlanMember" xlink:title="LongTermExecutiveIncentiveAndDeferredCompensationPlanMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="LongTermExecutiveIncentiveAndDeferredCompensationPlanMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to LongTermExecutiveIncentiveAndDeferredCompensationPlanMember" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_LongTermEquityIncentivePlanMember" xlink:label="LongTermEquityIncentivePlanMember" xlink:title="LongTermEquityIncentivePlanMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="LongTermEquityIncentivePlanMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to LongTermEquityIncentivePlanMember" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_EmployeeStockOptionAndIncentivePlan2011Member" xlink:label="EmployeeStockOptionAndIncentivePlan2011Member" xlink:title="EmployeeStockOptionAndIncentivePlan2011Member" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionAndIncentivePlan2011Member" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionAndIncentivePlan2011Member" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="RangeAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to RangeAxis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember" xlink:title="RangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeMember" xlink:title="definition: RangeAxis to RangeMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="RangeMember_2" xlink:title="RangeMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeMember_2" xlink:title="definition: RangeAxis to RangeMember" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MaximumMember" xlink:label="MaximumMember" xlink:title="MaximumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MaximumMember" xlink:title="definition: RangeMember to MaximumMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinimumMember" xlink:label="MinimumMember" xlink:title="MinimumMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeMember" xlink:to="MinimumMember" xlink:title="definition: RangeMember to MinimumMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ShareBasedCompensationArrangementByShareBasedPaymentAwardRollingPeriodOfMajorityAwardsToNonExecutiveOfficersAndDirectors" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardRollingPeriodOfMajorityAwardsToNonExecutiveOfficersAndDirectors" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardRollingPeriodOfMajorityAwardsToNonExecutiveOfficersAndDirectors" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardRollingPeriodOfMajorityAwardsToNonExecutiveOfficersAndDirectors" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardRollingPeriodOfMajorityAwardsToNonExecutiveOfficersAndDirectors" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMinimum" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMinimum" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMinimum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMinimum" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMinimum" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMaximum" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMaximum" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMaximum" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMaximum" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriodMaximum" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationDating" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationDating" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationDating" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationDating" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardExpirationDating" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to StockIssuedDuringPeriodSharesStockOptionsExercised" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" use="optional" order="8.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" order="2.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" use="optional" order="9.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm1" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualLifeAbstract to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" use="optional" order="10.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" use="optional" order="11.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" use="optional" order="12.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" use="optional" order="13.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod" use="optional" order="14.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" xlink:label="EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" xlink:title="EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationCashReceivedFromExerciseOfStockOptions" use="optional" order="15.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" xlink:label="EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" xlink:title="EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to EmployeeServiceShareBasedCompensationTaxBenefitRealizedFromExerciseOfStockOptions" use="optional" order="16.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:label="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:title="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ExcessTaxBenefitFromShareBasedCompensationFinancingActivities" use="optional" order="17.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureStockholdersEquityDetails3">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:label="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:title="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable to ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:to="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:title="definition: ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis to ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="EmployeeStockOptionMember" xlink:title="EmployeeStockOptionMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="EmployeeStockOptionMember" xlink:title="definition: ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain to EmployeeStockOptionMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsAndMethodologyAbstract" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" use="optional" order="5.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" use="optional" order="6.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedTerm" use="optional" order="7.0" />
    <loc xlink:type="locator" xlink:href="amg-20111231.xsd#amg_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate" xlink:title="definition: ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate" use="optional" order="8.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureValuationAndQualifyingAccountsDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:label="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:title="ValuationAndQualifyingAccountsDisclosureLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAndQualifyingAccountsDisclosureTable" xlink:label="ValuationAndQualifyingAccountsDisclosureTable" xlink:title="ValuationAndQualifyingAccountsDisclosureTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="ValuationAndQualifyingAccountsDisclosureTable" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to ValuationAndQualifyingAccountsDisclosureTable" order="1.0" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:label="ValuationAllowancesAndReservesTypeAxis" xlink:title="ValuationAllowancesAndReservesTypeAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ValuationAndQualifyingAccountsDisclosureTable" xlink:to="ValuationAllowancesAndReservesTypeAxis" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureTable to ValuationAllowancesAndReservesTypeAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="ValuationAllowancesAndReservesDomain" xlink:title="ValuationAllowancesAndReservesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ValuationAllowancesAndReservesTypeAxis" xlink:to="ValuationAllowancesAndReservesDomain" xlink:title="definition: ValuationAllowancesAndReservesTypeAxis to ValuationAllowancesAndReservesDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="ValuationAllowancesAndReservesDomain_2" xlink:title="ValuationAllowancesAndReservesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ValuationAllowancesAndReservesTypeAxis" xlink:to="ValuationAllowancesAndReservesDomain_2" xlink:title="definition: ValuationAllowancesAndReservesTypeAxis to ValuationAllowancesAndReservesDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember" xlink:label="ValuationAllowanceOfDeferredTaxAssetsMember" xlink:title="ValuationAllowanceOfDeferredTaxAssetsMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAllowancesAndReservesDomain" xlink:to="ValuationAllowanceOfDeferredTaxAssetsMember" xlink:title="definition: ValuationAllowancesAndReservesDomain to ValuationAllowanceOfDeferredTaxAssetsMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AllowanceForNotesReceivableMember" xlink:label="AllowanceForNotesReceivableMember" xlink:title="AllowanceForNotesReceivableMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAllowancesAndReservesDomain" xlink:to="AllowanceForNotesReceivableMember" xlink:title="definition: ValuationAllowancesAndReservesDomain to AllowanceForNotesReceivableMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward" xlink:label="MovementInValuationAllowancesAndReservesRollForward" xlink:title="MovementInValuationAllowancesAndReservesRollForward" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationAndQualifyingAccountsDisclosureLineItems" xlink:to="MovementInValuationAllowancesAndReservesRollForward" xlink:title="definition: ValuationAndQualifyingAccountsDisclosureLineItems to MovementInValuationAllowancesAndReservesRollForward" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:label="ValuationAllowancesAndReservesBalance" xlink:title="ValuationAllowancesAndReservesBalance" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MovementInValuationAllowancesAndReservesRollForward" xlink:to="ValuationAllowancesAndReservesBalance" xlink:title="definition: MovementInValuationAllowancesAndReservesRollForward to ValuationAllowancesAndReservesBalance" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:label="ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:title="ValuationAllowancesAndReservesChargedToCostAndExpense" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MovementInValuationAllowancesAndReservesRollForward" xlink:to="ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:title="definition: MovementInValuationAllowancesAndReservesRollForward to ValuationAllowancesAndReservesChargedToCostAndExpense" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:label="ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:title="ValuationAllowancesAndReservesChargedToOtherAccounts" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MovementInValuationAllowancesAndReservesRollForward" xlink:to="ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:title="definition: MovementInValuationAllowancesAndReservesRollForward to ValuationAllowancesAndReservesChargedToOtherAccounts" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDeductions" xlink:label="ValuationAllowancesAndReservesDeductions" xlink:title="ValuationAllowancesAndReservesDeductions" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MovementInValuationAllowancesAndReservesRollForward" xlink:to="ValuationAllowancesAndReservesDeductions" xlink:title="definition: MovementInValuationAllowancesAndReservesRollForward to ValuationAllowancesAndReservesDeductions" use="optional" order="4.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureInvestmentsDetails2">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:title="ScheduleOfAvailableForSaleSecuritiesLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="ScheduleOfAvailableForSaleSecuritiesTable" xlink:title="ScheduleOfAvailableForSaleSecuritiesTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="ScheduleOfAvailableForSaleSecuritiesTable" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesLineItems to ScheduleOfAvailableForSaleSecuritiesTable" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" xlink:title="ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesTable to ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:title="MajorTypesOfDebtAndEquitySecuritiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" xlink:to="MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis to MajorTypesOfDebtAndEquitySecuritiesDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="MajorTypesOfDebtAndEquitySecuritiesDomain_2" xlink:title="MajorTypesOfDebtAndEquitySecuritiesDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis" xlink:to="MajorTypesOfDebtAndEquitySecuritiesDomain_2" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesMajorTypesOfDebtAndEquitySecuritiesAxis to MajorTypesOfDebtAndEquitySecuritiesDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquitySecuritiesMember" xlink:label="EquitySecuritiesMember" xlink:title="EquitySecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:to="EquitySecuritiesMember" xlink:title="definition: MajorTypesOfDebtAndEquitySecuritiesDomain to EquitySecuritiesMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleEquitySecuritiesAmortizedCostBasis" xlink:label="AvailableForSaleEquitySecuritiesAmortizedCostBasis" xlink:title="AvailableForSaleEquitySecuritiesAmortizedCostBasis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="AvailableForSaleEquitySecuritiesAmortizedCostBasis" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesLineItems to AvailableForSaleEquitySecuritiesAmortizedCostBasis" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain" xlink:label="AvailableforsaleSecuritiesGrossUnrealizedGain" xlink:title="AvailableforsaleSecuritiesGrossUnrealizedGain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="AvailableforsaleSecuritiesGrossUnrealizedGain" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesLineItems to AvailableforsaleSecuritiesGrossUnrealizedGain" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1" xlink:label="AvailableForSaleSecuritiesGrossUnrealizedLosses1" xlink:title="AvailableForSaleSecuritiesGrossUnrealizedLosses1" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="AvailableForSaleSecuritiesGrossUnrealizedLosses1" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesLineItems to AvailableForSaleSecuritiesGrossUnrealizedLosses1" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AvailableForSaleSecuritiesFairValueDisclosure" xlink:label="AvailableForSaleSecuritiesFairValueDisclosure" xlink:title="AvailableForSaleSecuritiesFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="AvailableForSaleSecuritiesFairValueDisclosure" xlink:title="definition: ScheduleOfAvailableForSaleSecuritiesLineItems to AvailableForSaleSecuritiesFairValueDisclosure" use="optional" order="5.0" />
  </definitionLink>
  <definitionLink xlink:type="extended" xlink:role="http://www.amg.com/role/DisclosureInvestmentsDetails3">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:label="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:title="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:label="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:title="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" use="optional" order="1.0" xbrldt:contextElement="segment" xbrldt:closed="true" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:label="ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:title="ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:to="ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable to ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:label="MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:title="MajorTypesOfTradingSecuritiesAndAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:to="MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis to MajorTypesOfTradingSecuritiesAndAssetsDomain" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:label="MajorTypesOfTradingSecuritiesAndAssetsDomain_2" xlink:title="MajorTypesOfTradingSecuritiesAndAssetsDomain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis" xlink:to="MajorTypesOfTradingSecuritiesAndAssetsDomain_2" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsMajorTypesOfTradingSecuritiesAndAssetsAxis to MajorTypesOfTradingSecuritiesAndAssetsDomain" use="optional" priority="1" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquitySecuritiesMember" xlink:label="EquitySecuritiesMember" xlink:title="EquitySecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="EquitySecuritiesMember" xlink:title="definition: MajorTypesOfTradingSecuritiesAndAssetsDomain to EquitySecuritiesMember" use="optional" order="1.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtSecuritiesMember" xlink:label="DebtSecuritiesMember" xlink:title="DebtSecuritiesMember" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MajorTypesOfTradingSecuritiesAndAssetsDomain" xlink:to="DebtSecuritiesMember" xlink:title="definition: MajorTypesOfTradingSecuritiesAndAssetsDomain to DebtSecuritiesMember" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TradingSecurities" xlink:label="TradingSecurities" xlink:title="TradingSecurities" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="TradingSecurities" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to TradingSecurities" use="optional" order="2.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TradingSecuritiesUnrealizedHoldingGain" xlink:label="TradingSecuritiesUnrealizedHoldingGain" xlink:title="TradingSecuritiesUnrealizedHoldingGain" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="TradingSecuritiesUnrealizedHoldingGain" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to TradingSecuritiesUnrealizedHoldingGain" use="optional" order="3.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TradingSecuritiesUnrealizedHoldingLoss" xlink:label="TradingSecuritiesUnrealizedHoldingLoss" xlink:title="TradingSecuritiesUnrealizedHoldingLoss" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="TradingSecuritiesUnrealizedHoldingLoss" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to TradingSecuritiesUnrealizedHoldingLoss" use="optional" order="4.0" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_TradingSecuritiesFairValueDisclosure" xlink:label="TradingSecuritiesFairValueDisclosure" xlink:title="TradingSecuritiesFairValueDisclosure" />
    <definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:to="TradingSecuritiesFairValueDisclosure" xlink:title="definition: ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems to TradingSecuritiesFairValueDisclosure" use="optional" order="5.0" />
  </definitionLink>
</linkbase>
</XBRL>
