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  <xs:element id="acgl_TravelAndAccidentProductLineMember" abstract="true" name="TravelAndAccidentProductLineMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_Bellemeade20183Member" abstract="true" name="Bellemeade20183Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_SegmentOtherCostAndExpenseOperating" abstract="false" name="SegmentOtherCostAndExpenseOperating" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_PortionofIncomeOrLossAttributabletoMinorityInterestTableTextBlock" abstract="false" name="PortionofIncomeOrLossAttributabletoMinorityInterestTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="acgl_CasualtyMember" abstract="true" name="CasualtyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ScheduleOfOtherInvestmentsLineItems" abstract="true" name="ScheduleOfOtherInvestmentsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="acgl_ShortTailedLinesMember" abstract="true" name="ShortTailedLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_AcquisitionExpenseRatioPercentage" abstract="false" name="AcquisitionExpenseRatioPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="acgl_CombinedRatioPercentage" abstract="false" name="CombinedRatioPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="acgl_ProceedsFromPaymentsToNonredeemableNoncontrollingInterests" abstract="false" name="ProceedsFromPaymentsToNonredeemableNoncontrollingInterests" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_SPVIssuanceOfInsuranceLinkedNotes" abstract="false" name="SPVIssuanceOfInsuranceLinkedNotes" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_AmBestAminusOrBetterRatingMember" abstract="true" name="AmBestAminusOrBetterRatingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_OtherInvestmentsInfrastructureMember" abstract="true" name="OtherInvestmentsInfrastructureMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_InsuranceSegmentMember" abstract="true" name="InsuranceSegmentMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_MinorityInterestOtherAdjustmentstoAdditionalPaidinCapital" abstract="false" name="MinorityInterestOtherAdjustmentstoAdditionalPaidinCapital" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_Bellemeade20193LtdMember" abstract="true" name="Bellemeade20193LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_TreasuryStockValueAcquiredCumulativeSinceInception" abstract="false" name="TreasuryStockValueAcquiredCumulativeSinceInception" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_Bellemeade20192LtdMember" abstract="true" name="Bellemeade20192LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_NetRealizedGainsLosses" abstract="false" name="NetRealizedGainsLosses" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_InvestableAssets" abstract="false" name="InvestableAssets" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_MarineAndAviationProductLinesMember" abstract="true" name="MarineAndAviationProductLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_InitialCoverageAmount" abstract="false" name="InitialCoverageAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_Bellemeade20191LtdMember" abstract="true" name="Bellemeade20191LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_IncreaseDecreaseInLossAndLossAdjustmentExpensesNetOfRecoverables" abstract="false" name="IncreaseDecreaseInLossAndLossAdjustmentExpensesNetOfRecoverables" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_MediumTailedLinesMember" abstract="true" name="MediumTailedLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_NotRatedMember" abstract="true" name="NotRatedMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_CollateralOrGuaranteesAffiliatedTransactionsMember" abstract="true" name="CollateralOrGuaranteesAffiliatedTransactionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_SecuritiesLendingInvestmentsPledgedAmortizedCost" abstract="false" name="SecuritiesLendingInvestmentsPledgedAmortizedCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_TermLoanInvestmentsMember" abstract="true" name="TermLoanInvestmentsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_NoncontrollingOwnershipMember" abstract="true" name="NoncontrollingOwnershipMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_RedeemableNoncontrollingInterestAccretionofIssuanceCosts" abstract="false" name="RedeemableNoncontrollingInterestAccretionofIssuanceCosts" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_OtherInvestmentIncomeMember" abstract="true" name="OtherInvestmentIncomeMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_VariableInterestEntityCondensedBalanceSheetTableTextBlock" abstract="false" name="VariableInterestEntityCondensedBalanceSheetTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="acgl_NoncontrollingInterestRollforwardTableTextBlock" abstract="false" name="NoncontrollingInterestRollforwardTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="acgl_ProgramsMember" abstract="true" name="ProgramsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_KelsoAndCompanyMember" abstract="true" name="KelsoAndCompanyMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ProceedsfromRedemptionOfPreferredSharesByVariableInterestEntity" abstract="false" name="ProceedsfromRedemptionOfPreferredSharesByVariableInterestEntity" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_Bellemeade20202LtdMember" abstract="true" name="Bellemeade20202LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ExcessOfLossAgreementAggregateLosses" abstract="false" name="ExcessOfLossAgreementAggregateLosses" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_RedeemableNoncontrollingInterestDecreaseFromRedemptionsOrPurchaseOfInterests" abstract="false" name="RedeemableNoncontrollingInterestDecreaseFromRedemptionsOrPurchaseOfInterests" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_OtherUnderwritingIncomeLoss" abstract="false" name="OtherUnderwritingIncomeLoss" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_UnderwritingRelatedAllowanceForCreditLossesCreditLossExpenseReversal" abstract="false" name="UnderwritingRelatedAllowanceForCreditLossesCreditLossExpenseReversal" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_TbaMember" abstract="true" name="TbaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_BellemeadeRe20203LtdMember" abstract="true" name="BellemeadeRe20203LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ReinsuranceBusinessByTypeDomain" abstract="true" name="ReinsuranceBusinessByTypeDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ShortTailedAndLongTailedLinesMember" abstract="true" name="ShortTailedAndLongTailedLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_PropertyCatastropheMember" abstract="true" name="PropertyCatastropheMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_TotalAssetsAndLiabilitiesMeasuredAtFairValuePricedUsingNonBindingBrokerQuotes" abstract="false" name="TotalAssetsAndLiabilitiesMeasuredAtFairValuePricedUsingNonBindingBrokerQuotes" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_UnpaidReinsuranceRecoverablesandDeferredCharges" abstract="false" name="UnpaidReinsuranceRecoverablesandDeferredCharges" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_ShortTermInvestmentsFairValueOptionMember" abstract="true" name="ShortTermInvestmentsFairValueOptionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_AvailableForSaleSecuritiesQualitativeDisclosureLargestSingleLoss" abstract="false" name="AvailableForSaleSecuritiesQualitativeDisclosureLargestSingleLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_FairValueOptionMember" abstract="true" name="FairValueOptionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ContractholderReceivablesAllowanceForCreditLoss" abstract="false" name="ContractholderReceivablesAllowanceForCreditLoss" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_ScheduleOfRestrictedAssetsTable" abstract="true" name="ScheduleOfRestrictedAssetsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="acgl_DepositsWithUsRegulatoryAuthoritiesMember" abstract="true" name="DepositsWithUsRegulatoryAuthoritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_CollateralOrGuaranteesThirdPartyAgreementsMember" abstract="true" name="CollateralOrGuaranteesThirdPartyAgreementsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_RestrictedAssetsTableTextBlock" abstract="false" name="RestrictedAssetsTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="acgl_ShortTailedAndMediumTailedLinesMember" abstract="true" name="ShortTailedAndMediumTailedLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_OtherInvestmentsRealEstateMember" abstract="true" name="OtherInvestmentsRealEstateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_SecuritiesReceivedAsCollateralAmortizedCost" abstract="false" name="SecuritiesReceivedAsCollateralAmortizedCost" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_EquitySecuritiesFairValueOptionMember" abstract="true" name="EquitySecuritiesFairValueOptionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_AvailableForSaleSecuritiesQualitativeDisclosureNumberOfPositions" abstract="false" name="AvailableForSaleSecuritiesQualitativeDisclosureNumberOfPositions" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="acgl_ExecutiveAssuranceAndCasualtyProductLinesMember" abstract="true" name="ExecutiveAssuranceAndCasualtyProductLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_RestrictedAssetsRestrictionTypeAxis" abstract="true" name="RestrictedAssetsRestrictionTypeAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="acgl_BellemeadeRe20181LtdMember" abstract="true" name="BellemeadeRe20181LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ExcessOfLossAgreementPeriod" abstract="false" name="ExcessOfLossAgreementPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="us-types:durationStringItemType"/>
  <xs:element id="acgl_BellemeadeRe20194LtdMember" abstract="true" name="BellemeadeRe20194LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_Bellemeade20171LtdMember" abstract="true" name="Bellemeade20171LtdMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_ShortTermInvestmentsCostAmount" abstract="false" name="ShortTermInvestmentsCostAmount" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_NoncontrollingInterestPeriodIncreaseDecreaseOther" abstract="false" name="NoncontrollingInterestPeriodIncreaseDecreaseOther" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_AggregateExcessOfLossReinsuranceAgreement" abstract="false" name="AggregateExcessOfLossReinsuranceAgreement" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_ContractBindingBusinessMember" abstract="true" name="ContractBindingBusinessMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_VariableInterestEntityMaximumExposureToLossTableTextBlock" abstract="false" name="VariableInterestEntityMaximumExposureToLossTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType"/>
  <xs:element id="acgl_SourcesOfFundingDomain" abstract="true" name="SourcesOfFundingDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_DepositsWithNonUsRegulatoryAuthoritiesMember" abstract="true" name="DepositsWithNonUsRegulatoryAuthoritiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_DirectlyProvidedCapacityMember" abstract="true" name="DirectlyProvidedCapacityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsRetroactiveReinsurance" abstract="false" name="LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaimsRetroactiveReinsurance" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_SourcesOfFundingAxis" abstract="true" name="SourcesOfFundingAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="acgl_OtherOperatingExpenseRatioPercentage" abstract="false" name="OtherOperatingExpenseRatioPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="num:percentItemType"/>
  <xs:element id="acgl_MediumTailedAndLongTailedLinesMember" abstract="true" name="MediumTailedAndLongTailedLinesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="nonnum:domainItemType"/>
  <xs:element id="acgl_VariableInterestEntityMaximumExposuretoLossOffBalanceSheet" abstract="false" name="VariableInterestEntityMaximumExposuretoLossOffBalanceSheet" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="acgl_ContractHolderPayables" abstract="false" name="ContractHolderPayables" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
