<?xml version="1.0" encoding="US-ASCII"?>
<!--XBRL Document Created with WebFilings-->
<!-- -->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <link:roleRef roleURI="http://www.seic.com/role/AccumulatedComprehensiveIncomeLossScheduleOfAccumulatedOtherComprehensiveIncomeLossNetOfTaxDetails" xlink:href="seic-20121231.xsd#AccumulatedComprehensiveIncomeLossScheduleOfAccumulatedOtherComprehensiveIncomeLossNetOfTaxDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/BusinessSegmentInformationBusinessSegmentInformationScheduleOfRevenuesAndAssetsBasedOnLocationDetails" xlink:href="seic-20121231.xsd#BusinessSegmentInformationBusinessSegmentInformationScheduleOfRevenuesAndAssetsBasedOnLocationDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/BusinessSegmentInformationReconciliationOfTotalOperatingProfitReportedForBusinessSegmentsToIncomeFromOperationsInConsolidatedStatementsOfOperationsDetails" xlink:href="seic-20121231.xsd#BusinessSegmentInformationReconciliationOfTotalOperatingProfitReportedForBusinessSegmentsToIncomeFromOperationsInConsolidatedStatementsOfOperationsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/BusinessSegmentInformationScheduleOfAdditionalInformationPertainingToBusinessSegmentsDetails" xlink:href="seic-20121231.xsd#BusinessSegmentInformationScheduleOfAdditionalInformationPertainingToBusinessSegmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/BusinessSegmentInformationScheduleOfFinancialInformationAboutBusinessSegmentsDetails" xlink:href="seic-20121231.xsd#BusinessSegmentInformationScheduleOfFinancialInformationAboutBusinessSegmentsDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/ConsolidatedStatementsOfChangesInEquity" xlink:href="seic-20121231.xsd#ConsolidatedStatementsOfChangesInEquity" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/DocumentAndEntityInformation" xlink:href="seic-20121231.xsd#DocumentAndEntityInformation" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/FairValueMeasurementsFairValueOfCertainFinancialAssetsAndLiabilitiesDetails" xlink:href="seic-20121231.xsd#FairValueMeasurementsFairValueOfCertainFinancialAssetsAndLiabilitiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/FairValueMeasurementsNarrativeDetails" xlink:href="seic-20121231.xsd#FairValueMeasurementsNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/FairValueMeasurementsReconciliationForAllAssetsAndLiabilitiesOfCompanyMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsLevel3Details" xlink:href="seic-20121231.xsd#FairValueMeasurementsReconciliationForAllAssetsAndLiabilitiesOfCompanyMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsLevel3Details" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/InvestmentInUnconsolidatedAffiliatesInvestmentInUnconsolidatedAffiliatesCondensedBalanceSheetsOfLsvDetails" xlink:href="seic-20121231.xsd#InvestmentInUnconsolidatedAffiliatesInvestmentInUnconsolidatedAffiliatesCondensedBalanceSheetsOfLsvDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/InvestmentInUnconsolidatedAffiliatesInvestmentInUnconsolidatedAffiliatesCondensedStatementsOfOperationsOfLsvDetails" xlink:href="seic-20121231.xsd#InvestmentInUnconsolidatedAffiliatesInvestmentInUnconsolidatedAffiliatesCondensedStatementsOfOperationsOfLsvDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/InvestmentInUnconsolidatedAffiliatesNarrativeDetails" xlink:href="seic-20121231.xsd#InvestmentInUnconsolidatedAffiliatesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/LinesOfCreditDetails" xlink:href="seic-20121231.xsd#LinesOfCreditDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/MarketableSecuritiesInvestmentsAvailableForSaleDetails" xlink:href="seic-20121231.xsd#MarketableSecuritiesInvestmentsAvailableForSaleDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/MarketableSecuritiesNarrativeDetails" xlink:href="seic-20121231.xsd#MarketableSecuritiesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/MarketableSecuritiesTradingSecuritiesDetails" xlink:href="seic-20121231.xsd#MarketableSecuritiesTradingSecuritiesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/QuarterlyFinancialDataSivRelatedGainsLossesDetails" xlink:href="seic-20121231.xsd#QuarterlyFinancialDataSivRelatedGainsLossesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/SaleOfSeiAssetKoreaSaleOfSeiAssetKoreaNarrativeDetails" xlink:href="seic-20121231.xsd#SaleOfSeiAssetKoreaSaleOfSeiAssetKoreaNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/ScheduleIiValuationAndQualifyingAccountsAndReservesDetails" xlink:href="seic-20121231.xsd#ScheduleIiValuationAndQualifyingAccountsAndReservesDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/ShareholdersEquityNarrativeDetails" xlink:href="seic-20121231.xsd#ShareholdersEquityNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/ShareholdersEquityScheduleOfReconciliationOfNoncontrollingInterestOnConsolidatedBalanceSheetDetails" xlink:href="seic-20121231.xsd#ShareholdersEquityScheduleOfReconciliationOfNoncontrollingInterestOnConsolidatedBalanceSheetDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/ShareholdersEquityStockOptionPlansDetails" xlink:href="seic-20121231.xsd#ShareholdersEquityStockOptionPlansDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/ShareholdersEquityStockOptionsOutstandingAndExercisableDetails" xlink:href="seic-20121231.xsd#ShareholdersEquityStockOptionsOutstandingAndExercisableDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:href="seic-20121231.xsd#SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" />
  <link:roleRef roleURI="http://www.seic.com/role/VariableInterestEntitiesInvestmentProductsDetails" xlink:href="seic-20121231.xsd#VariableInterestEntitiesInvestmentProductsDetails" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" xlink:type="simple" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" xlink:type="simple" />
  <link:definitionLink xlink:role="http://www.seic.com/role/AccumulatedComprehensiveIncomeLossScheduleOfAccumulatedOtherComprehensiveIncomeLossNetOfTaxDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_66D59FB4174DB8ABA305FE2D3DC9B7A4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_StatementTable_66D59FB4174DB8ABA305FE2D3DC9B7A4" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_36F9DF4704358DF83165FE2D3DC98FC1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_66D59FB4174DB8ABA305FE2D3DC9B7A4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_36F9DF4704358DF83165FE2D3DC98FC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_761462C168F623BDE491FE2D3DC9B584_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_36F9DF4704358DF83165FE2D3DC98FC1" xlink:to="loc_us-gaap_EquityComponentDomain_761462C168F623BDE491FE2D3DC9B584_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_761462C168F623BDE491FE2D3DC9B584" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_36F9DF4704358DF83165FE2D3DC98FC1" xlink:to="loc_us-gaap_EquityComponentDomain_761462C168F623BDE491FE2D3DC9B584" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParentMember" xlink:label="loc_us-gaap_ParentMember_749C12092C0E84F76D95FE2D3DC984D8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_761462C168F623BDE491FE2D3DC9B584" xlink:to="loc_us-gaap_ParentMember_749C12092C0E84F76D95FE2D3DC984D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_4E2B0DF810EE8E115584FE2D3DC96E31" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_761462C168F623BDE491FE2D3DC9B584" xlink:to="loc_us-gaap_NoncontrollingInterestMember_4E2B0DF810EE8E115584FE2D3DC96E31" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_F86B98F910E0265B47D6FE2D3DC90F06" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossForeignCurrencyTranslationAdjustmentNetOfTax_F86B98F910E0265B47D6FE2D3DC90F06" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_27BD328A7FF8BACA45E2FE2D3DC9FBDE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_27BD328A7FF8BACA45E2FE2D3DC9FBDE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_294068B2805DE27FE6F6FE2D3DC909DE" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_294068B2805DE27FE6F6FE2D3DC909DE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_2D017F8646A911C8AD47FE2D3DC99601" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_2D017F8646A911C8AD47FE2D3DC99601" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_69CF94378FAC773EF127FE2D3DC9308A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_69CF94378FAC773EF127FE2D3DC9308A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_C3184BAECDB0ADAF6AFAFE2D3DC90428" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_C3184BAECDB0ADAF6AFAFE2D3DC90428" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest_3A4FA5B137A0484A5025FE2D3DC9351B" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest_3A4FA5B137A0484A5025FE2D3DC9351B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest_79E87D85114D57469878FE2D3DC9D1BC" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest_79E87D85114D57469878FE2D3DC9D1BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_883FFCCFC34D0F66BBD1FE2D3DC9BF37" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest_883FFCCFC34D0F66BBD1FE2D3DC9BF37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_71B0F9FD9D13BFCEB580FE2D3DC948D0" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_71B0F9FD9D13BFCEB580FE2D3DC948D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_F0BDD513ECDE0DA4E81CFE2D3DC97E9C" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_F0BDD513ECDE0DA4E81CFE2D3DC97E9C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_C584E7F2152308836C1FFE2D3DC9C249" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01E415FD5C1BDB229948FE2D3DC975E8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_C584E7F2152308836C1FFE2D3DC9C249" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/BusinessSegmentInformationBusinessSegmentInformationScheduleOfRevenuesAndAssetsBasedOnLocationDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_D1A0E19BF075C6CD72CCF2F2715E71A1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_040CB5E0E580CF6EAF9BF2F2715E69F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_D1A0E19BF075C6CD72CCF2F2715E71A1" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_040CB5E0E580CF6EAF9BF2F2715E69F0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementGeographicalAxis" xlink:label="loc_us-gaap_StatementGeographicalAxis_D82A1E03D2A122CDF6C7F2F2715EE6DC" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_040CB5E0E580CF6EAF9BF2F2715E69F0" xlink:to="loc_us-gaap_StatementGeographicalAxis_D82A1E03D2A122CDF6C7F2F2715EE6DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_601A20BD96E09EB58879F2F2715E926F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementGeographicalAxis_D82A1E03D2A122CDF6C7F2F2715EE6DC" xlink:to="loc_us-gaap_SegmentGeographicalDomain_601A20BD96E09EB58879F2F2715E926F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentGeographicalDomain" xlink:label="loc_us-gaap_SegmentGeographicalDomain_601A20BD96E09EB58879F2F2715E926F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementGeographicalAxis_D82A1E03D2A122CDF6C7F2F2715EE6DC" xlink:to="loc_us-gaap_SegmentGeographicalDomain_601A20BD96E09EB58879F2F2715E926F" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_UnitedStatesMember" xlink:label="loc_seic_UnitedStatesMember_70B19AB0AAFD523E26CFF2F2715E2EC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_601A20BD96E09EB58879F2F2715E926F" xlink:to="loc_seic_UnitedStatesMember_70B19AB0AAFD523E26CFF2F2715E2EC2" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InternationalOperationsMember" xlink:label="loc_seic_InternationalOperationsMember_BE7B597E5E43A57C2206F2F2715E948D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentGeographicalDomain_601A20BD96E09EB58879F2F2715E926F" xlink:to="loc_seic_InternationalOperationsMember_BE7B597E5E43A57C2206F2F2715E948D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_600AA5F638AE2832A9FDF2F2715E7E87" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_D1A0E19BF075C6CD72CCF2F2715E71A1" xlink:to="loc_us-gaap_Revenues_600AA5F638AE2832A9FDF2F2715E7E87" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_091D29847E15D731EB2DF2F2715E2FD8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_D1A0E19BF075C6CD72CCF2F2715E71A1" xlink:to="loc_us-gaap_Assets_091D29847E15D731EB2DF2F2715E2FD8" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/BusinessSegmentInformationReconciliationOfTotalOperatingProfitReportedForBusinessSegmentsToIncomeFromOperationsInConsolidatedStatementsOfOperationsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_D7775FB946DB012B82D0F8D8C1E5059A" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_50E9438F5D545B55BE47F8D8C1E5FA0F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_D7775FB946DB012B82D0F8D8C1E5059A" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_50E9438F5D545B55BE47F8D8C1E5FA0F" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_F28FC0B692B5EC70BE28F8D8C1E54759" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_50E9438F5D545B55BE47F8D8C1E5FA0F" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_F28FC0B692B5EC70BE28F8D8C1E54759" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_8D9329740F9CAF81731BF8D8C1E522F9_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_F28FC0B692B5EC70BE28F8D8C1E54759" xlink:to="loc_us-gaap_SegmentDomain_8D9329740F9CAF81731BF8D8C1E522F9_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_8D9329740F9CAF81731BF8D8C1E522F9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_F28FC0B692B5EC70BE28F8D8C1E54759" xlink:to="loc_us-gaap_SegmentDomain_8D9329740F9CAF81731BF8D8C1E522F9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_7BE35A7DD9231E95A415F8DCBCAB3107" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_D7775FB946DB012B82D0F8D8C1E5059A" xlink:to="loc_us-gaap_GrossProfit_7BE35A7DD9231E95A415F8DCBCAB3107" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_9153ADEC2F7958E68F5EF8D8C1E56C79" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_D7775FB946DB012B82D0F8D8C1E5059A" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_9153ADEC2F7958E68F5EF8D8C1E56C79" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinorityInterestInNetIncomeLossOtherMinorityInterests" xlink:label="loc_us-gaap_MinorityInterestInNetIncomeLossOtherMinorityInterests_9DDA08620967CE36BC6DF8D8C1E50153" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_D7775FB946DB012B82D0F8D8C1E5059A" xlink:to="loc_us-gaap_MinorityInterestInNetIncomeLossOtherMinorityInterests_9DDA08620967CE36BC6DF8D8C1E50153" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaap_OperatingIncomeLoss_1592FCD76397817C305BF8D8C1E57AFD" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_D7775FB946DB012B82D0F8D8C1E5059A" xlink:to="loc_us-gaap_OperatingIncomeLoss_1592FCD76397817C305BF8D8C1E57AFD" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/BusinessSegmentInformationScheduleOfAdditionalInformationPertainingToBusinessSegmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_384CA5EF24F6680B00564066C73581AD" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3C92D71406113C90879D4066C735DC65" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_384CA5EF24F6680B00564066C73581AD" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3C92D71406113C90879D4066C735DC65" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_863B670C63191ADFBA3B4066C735FFF7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3C92D71406113C90879D4066C735DC65" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_863B670C63191ADFBA3B4066C735FFF7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_863B670C63191ADFBA3B4066C735FFF7" xlink:to="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_863B670C63191ADFBA3B4066C735FFF7" xlink:to="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_PrivateBankMember" xlink:label="loc_seic_PrivateBankMember_C1FCFD3935A40A9F50784066C735FC44" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_PrivateBankMember_C1FCFD3935A40A9F50784066C735FC44" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InvestmentAdvisorsMember" xlink:label="loc_seic_InvestmentAdvisorsMember_3F90B916FC1EE1C46E3B4066C73548DC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_InvestmentAdvisorsMember_3F90B916FC1EE1C46E3B4066C73548DC" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InstitutionalInvestorsMember" xlink:label="loc_seic_InstitutionalInvestorsMember_58520691A040C448094C4066C735F383" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_InstitutionalInvestorsMember_58520691A040C448094C4066C735F383" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InvestmentManagersMember" xlink:label="loc_seic_InvestmentManagersMember_95ECCC14E98FC195C4CD4066C7353068" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_InvestmentManagersMember_95ECCC14E98FC195C4CD4066C7353068" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InvestmentsInNewBusinessesMember" xlink:label="loc_seic_InvestmentsInNewBusinessesMember_3D3482022963A518C9974066C7356A61" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_InvestmentsInNewBusinessesMember_3D3482022963A518C9974066C7356A61" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_TotalFromBusinessSegmentsMember" xlink:label="loc_seic_TotalFromBusinessSegmentsMember_9A512E689FA62D295A164066C735DF32" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_TotalFromBusinessSegmentsMember_9A512E689FA62D295A164066C735DF32" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CorporateOverheadMember" xlink:label="loc_seic_CorporateOverheadMember_5980776A0684D709E4274066C73533D0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_6895602F99FFF139F8F24066C735B1A1" xlink:to="loc_seic_CorporateOverheadMember_5980776A0684D709E4274066C73533D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_B28CB16730A07CE62C814066C735F00A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_384CA5EF24F6680B00564066C73581AD" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_B28CB16730A07CE62C814066C735F00A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_6C889F9CD34FBAF8FFF64066C7358DC2" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_384CA5EF24F6680B00564066C73581AD" xlink:to="loc_us-gaap_Depreciation_6C889F9CD34FBAF8FFF64066C7358DC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="loc_us-gaap_AdjustmentForAmortization_F7E3FC72E353F30A58724066C735546A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_384CA5EF24F6680B00564066C73581AD" xlink:to="loc_us-gaap_AdjustmentForAmortization_F7E3FC72E353F30A58724066C735546A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_437CF485FC19E50E0612406DAD5146A9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_384CA5EF24F6680B00564066C73581AD" xlink:to="loc_us-gaap_Assets_437CF485FC19E50E0612406DAD5146A9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/BusinessSegmentInformationScheduleOfFinancialInformationAboutBusinessSegmentsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_68E4037EE542070C9DF1F8D714DB0AE7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ADD1DAAA2AC3161F1E22F8D714DB202A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_68E4037EE542070C9DF1F8D714DB0AE7" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ADD1DAAA2AC3161F1E22F8D714DB202A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_76B5F55CD2A7BF8E89B6F8D714DB44AA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_ADD1DAAA2AC3161F1E22F8D714DB202A" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_76B5F55CD2A7BF8E89B6F8D714DB44AA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_76B5F55CD2A7BF8E89B6F8D714DB44AA" xlink:to="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_76B5F55CD2A7BF8E89B6F8D714DB44AA" xlink:to="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_PrivateBankMember" xlink:label="loc_seic_PrivateBankMember_BD97891500F1905302D8F8D714DBF03E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:to="loc_seic_PrivateBankMember_BD97891500F1905302D8F8D714DBF03E" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InvestmentAdvisorsMember" xlink:label="loc_seic_InvestmentAdvisorsMember_70FA2682348572F8DD63F8D714DBF731" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:to="loc_seic_InvestmentAdvisorsMember_70FA2682348572F8DD63F8D714DBF731" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InstitutionalInvestorsMember" xlink:label="loc_seic_InstitutionalInvestorsMember_D45D59F14A0A0B24B160F8D714DB0435" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:to="loc_seic_InstitutionalInvestorsMember_D45D59F14A0A0B24B160F8D714DB0435" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InvestmentManagersMember" xlink:label="loc_seic_InvestmentManagersMember_A0C68FBA5E1A6AB6BDE7F8D714DBAA86" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:to="loc_seic_InvestmentManagersMember_A0C68FBA5E1A6AB6BDE7F8D714DBAA86" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InvestmentsInNewBusinessesMember" xlink:label="loc_seic_InvestmentsInNewBusinessesMember_E3486335389AFC696D6FF8D714DB52FE" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2F8D0B8ABB627A592980F8D714DBCB85" xlink:to="loc_seic_InvestmentsInNewBusinessesMember_E3486335389AFC696D6FF8D714DB52FE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_8F930932D67FAED853B8F8D714DB5579" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_68E4037EE542070C9DF1F8D714DB0AE7" xlink:to="loc_us-gaap_Revenues_8F930932D67FAED853B8F8D714DB5579" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OperatingCostsAndExpenses" xlink:label="loc_us-gaap_OperatingCostsAndExpenses_ED00FA299E7AA5F76632F8D714DBB298" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_68E4037EE542070C9DF1F8D714DB0AE7" xlink:to="loc_us-gaap_OperatingCostsAndExpenses_ED00FA299E7AA5F76632F8D714DBB298" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaap_GrossProfit_3853347099D14C923BB3F8D7EF4E6C91" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_68E4037EE542070C9DF1F8D714DB0AE7" xlink:to="loc_us-gaap_GrossProfit_3853347099D14C923BB3F8D7EF4E6C91" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SegmentReportingInformationOperatingMarginPercentage" xlink:label="loc_seic_SegmentReportingInformationOperatingMarginPercentage_AD9C42780E0C8D5B3788F8D714DBDF6B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_68E4037EE542070C9DF1F8D714DB0AE7" xlink:to="loc_seic_SegmentReportingInformationOperatingMarginPercentage_AD9C42780E0C8D5B3788F8D714DBDF6B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/ConsolidatedStatementsOfChangesInEquity" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_E985140235116FC6B0E9EDEF95A3828B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_458381ED67CED5B74E30EDEF95A3303A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_E985140235116FC6B0E9EDEF95A3828B" xlink:to="loc_us-gaap_StatementTable_458381ED67CED5B74E30EDEF95A3303A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_65E803CD11276911B198EDEF95A3D6B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_458381ED67CED5B74E30EDEF95A3303A" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_65E803CD11276911B198EDEF95A3D6B3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_65E803CD11276911B198EDEF95A3D6B3" xlink:to="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_65E803CD11276911B198EDEF95A3D6B3" xlink:to="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_BCD1B00F0C18C349ADC0EDEF95A30366" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:to="loc_us-gaap_CommonStockMember_BCD1B00F0C18C349ADC0EDEF95A30366" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_7C4209078009EF1F6B21EDEF95A3F10C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_7C4209078009EF1F6B21EDEF95A3F10C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaap_RetainedEarningsMember_6696B3CEF6A26AF62C58EDEF95A3AA25" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:to="loc_us-gaap_RetainedEarningsMember_6696B3CEF6A26AF62C58EDEF95A3AA25" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_69CA65B8489139D2315DEDEF95A34950" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_69CA65B8489139D2315DEDEF95A34950" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ParentMember" xlink:label="loc_us-gaap_ParentMember_E767D6F734D38C7B0081EDEF95A34A82" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:to="loc_us-gaap_ParentMember_E767D6F734D38C7B0081EDEF95A34A82" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_286AD35DD651F9423D42EDEF95A326D9" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6B99E8FCF58C76BB74EBEDEF95A35D94" xlink:to="loc_us-gaap_NoncontrollingInterestMember_286AD35DD651F9423D42EDEF95A326D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_E985140235116FC6B0E9EDEF95A3828B" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_C4AFC25984DCC1D3B0F3EDEF95A3666B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_C4AFC25984DCC1D3B0F3EDEF95A3666B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaap_CommonStockSharesIssued_43AD106F58D9D262D5C2EDEF95A3CA1C" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_CommonStockSharesIssued_43AD106F58D9D262D5C2EDEF95A3CA1C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_B7C2923D71987AB46274EDEF95A3427F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_NetIncomeLoss_B7C2923D71987AB46274EDEF95A3427F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_EDEE0D80F8F98CAF5FFDEDEF95A334EA" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodValue_EDEE0D80F8F98CAF5FFDEDEF95A334EA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_C802C898146C81395362EDEF95A3AAC8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_C802C898146C81395362EDEF95A3AAC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_A44478521DBEB323FD3EEDEF95A3BAB2" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_A44478521DBEB323FD3EEDEF95A3BAB2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_B2A056E9D3B4E805B75BEDEF95A3EF0F" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_B2A056E9D3B4E805B75BEDEF95A3EF0F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_79604D145A2C84277FE8EDEF95A3EE2A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_79604D145A2C84277FE8EDEF95A3EE2A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_195039D5CA43594C7FA0EDEF95A334C9" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_195039D5CA43594C7FA0EDEF95A334C9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_942DFF02D4A8B10DF77BEDEF95A35E42" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_942DFF02D4A8B10DF77BEDEF95A35E42" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation_450B885F7E4A89E182D1EDEF95A3449A" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalTaxEffectFromShareBasedCompensation_450B885F7E4A89E182D1EDEF95A3449A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DividendsCommonStock" xlink:label="loc_us-gaap_DividendsCommonStock_9D87B757ACEDF4EBDDF9EDEF95A335CF" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_DividendsCommonStock_9D87B757ACEDF4EBDDF9EDEF95A335CF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_C30205147CBBB157156FEDEF95A3B7EC" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_C30205147CBBB157156FEDEF95A3B7EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaap_StockholdersEquity_4CB8D9ABBF533D93A708EDEF95A33712" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_StockholdersEquity_4CB8D9ABBF533D93A708EDEF95A33712" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_BA1B27831FDEAC4DB64DEDEF95A354C5" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_B1A0BE2DB41CDB6A341DEDEF95A31BA1" xlink:to="loc_us-gaap_MinorityInterest_BA1B27831FDEAC4DB64DEDEF95A354C5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/DocumentAndEntityInformation" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentInformationLineItems" xlink:label="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentInformationTable" xlink:label="loc_dei_DocumentInformationTable_A3861AE190EED9C97DD8F521F11AC487" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_DocumentInformationTable_A3861AE190EED9C97DD8F521F11AC487" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentInformationDocumentAxis" xlink:label="loc_dei_DocumentInformationDocumentAxis_42D1A27F1635D3DF3419F521F11A2786" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_DocumentInformationTable_A3861AE190EED9C97DD8F521F11AC487" xlink:to="loc_dei_DocumentInformationDocumentAxis_42D1A27F1635D3DF3419F521F11A2786" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentDomain" xlink:label="loc_dei_DocumentDomain_BF43B0A9B0FD70A2E51FF521F11A95BD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_DocumentInformationDocumentAxis_42D1A27F1635D3DF3419F521F11A2786" xlink:to="loc_dei_DocumentDomain_BF43B0A9B0FD70A2E51FF521F11A95BD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentDomain" xlink:label="loc_dei_DocumentDomain_BF43B0A9B0FD70A2E51FF521F11A95BD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_DocumentInformationDocumentAxis_42D1A27F1635D3DF3419F521F11A2786" xlink:to="loc_dei_DocumentDomain_BF43B0A9B0FD70A2E51FF521F11A95BD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityRegistrantName" xlink:label="loc_dei_EntityRegistrantName_A89942C9C3664B65974EF521F11AA1F0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityRegistrantName_A89942C9C3664B65974EF521F11AA1F0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityCentralIndexKey" xlink:label="loc_dei_EntityCentralIndexKey_7098A8D4FCF78BB5A189F521F11B7624" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityCentralIndexKey_7098A8D4FCF78BB5A189F521F11B7624" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_CurrentFiscalYearEndDate" xlink:label="loc_dei_CurrentFiscalYearEndDate_2D4EECB4E890175D2B94F521F11BF1A4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_CurrentFiscalYearEndDate_2D4EECB4E890175D2B94F521F11BF1A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityFilerCategory" xlink:label="loc_dei_EntityFilerCategory_757BEDCFE6112B0A253AF521F11BCF4D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityFilerCategory_757BEDCFE6112B0A253AF521F11BCF4D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentType" xlink:label="loc_dei_DocumentType_8CFBDA4F6846C15D6E87F521F11B7FCB" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_DocumentType_8CFBDA4F6846C15D6E87F521F11B7FCB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentPeriodEndDate" xlink:label="loc_dei_DocumentPeriodEndDate_B4583C1D0D5C04C9A766F521F11B28C7" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_DocumentPeriodEndDate_B4583C1D0D5C04C9A766F521F11B28C7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentFiscalYearFocus" xlink:label="loc_dei_DocumentFiscalYearFocus_1317811CBD4F3E721137F521F11B36B0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_DocumentFiscalYearFocus_1317811CBD4F3E721137F521F11B36B0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="loc_dei_DocumentFiscalPeriodFocus_2CA6D6465EF9B46669ABF521F11BC5DC" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_DocumentFiscalPeriodFocus_2CA6D6465EF9B46669ABF521F11BC5DC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_TradingSymbol" xlink:label="loc_dei_TradingSymbol_24F73E50E54B8F07AE1CF521F11BF7F7" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_TradingSymbol_24F73E50E54B8F07AE1CF521F11BF7F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_AmendmentFlag" xlink:label="loc_dei_AmendmentFlag_D2B9071CC0707D04849EF521F11B0EEF" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_AmendmentFlag_D2B9071CC0707D04849EF521F11B0EEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_76DCB2F7A489505A1CD6F521F11B26D0" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_76DCB2F7A489505A1CD6F521F11B26D0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityPublicFloat" xlink:label="loc_dei_EntityPublicFloat_DB400C438C328594E4CEF521F11BDF21" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityPublicFloat_DB400C438C328594E4CEF521F11BDF21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="loc_dei_EntityWellKnownSeasonedIssuer_2B5C2B4DD41E36B972A7F52285D7544A" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityWellKnownSeasonedIssuer_2B5C2B4DD41E36B972A7F52285D7544A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityVoluntaryFilers" xlink:label="loc_dei_EntityVoluntaryFilers_BCCFF1D5480F4F429027F522F9164FCE" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityVoluntaryFilers_BCCFF1D5480F4F429027F522F9164FCE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityCurrentReportingStatus" xlink:label="loc_dei_EntityCurrentReportingStatus_D59A84E34400577E0994F52395AACD82" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_DocumentInformationLineItems_8BA8D89E32FD99BA9638F521F11AC9BA" xlink:to="loc_dei_EntityCurrentReportingStatus_D59A84E34400577E0994F52395AACD82" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/FairValueMeasurementsFairValueOfCertainFinancialAssetsAndLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_13564AA642883F238332255B6A4196CA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_13564AA642883F238332255B6A4196CA" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_F77F8B4501626C08015D255B6A412F78" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_13564AA642883F238332255B6A4196CA" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_F77F8B4501626C08015D255B6A412F78" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_F77F8B4501626C08015D255B6A412F78" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_F77F8B4501626C08015D255B6A412F78" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_312E7713613E2EE39E62255B6A41EBD3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_312E7713613E2EE39E62255B6A41EBD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_FC131832C9BAC22C1820255B6A4107E4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_FC131832C9BAC22C1820255B6A4107E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_4F2DDBA5C32E8C6930FD255B6A41E28E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_73CA867537634E7610C8255B6A417D4A" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_4F2DDBA5C32E8C6930FD255B6A41E28E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesEquitySecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesEquitySecurities_56EF14D6E93D1725135D255B6A417259" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesEquitySecurities_56EF14D6E93D1725135D255B6A417259" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_E30EE3B0F1B006F17440255B6A4194BC" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_E30EE3B0F1B006F17440255B6A4194BC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue" xlink:label="loc_us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue_B80BB50EE78068EC70AD255B6A41E7F3" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:to="loc_us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue_B80BB50EE78068EC70AD255B6A41E7F3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesEquity" xlink:label="loc_us-gaap_TradingSecuritiesEquity_02E508CC3F29F8D1D71C255B6A410A9A" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:to="loc_us-gaap_TradingSecuritiesEquity_02E508CC3F29F8D1D71C255B6A410A9A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_A3C02FF1DA9EC225FDA1255B6A41A0D5" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_ED972413B8FDC7C9475B255B6A4125EE" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_A3C02FF1DA9EC225FDA1255B6A41A0D5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_61C13C82E0F06D951E96835ADF506CEA" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8E7E4A29FB13A513BBCF835ADF500F04" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_61C13C82E0F06D951E96835ADF506CEA" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8E7E4A29FB13A513BBCF835ADF500F04" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_7298EAFA68CDC44A5EE3836890876261" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8E7E4A29FB13A513BBCF835ADF500F04" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_7298EAFA68CDC44A5EE3836890876261" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_A13795820F26A55EC9B583689181B37F_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_7298EAFA68CDC44A5EE3836890876261" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_A13795820F26A55EC9B583689181B37F_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_A13795820F26A55EC9B583689181B37F" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_7298EAFA68CDC44A5EE3836890876261" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_A13795820F26A55EC9B583689181B37F" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_GryphonSivMember" xlink:label="loc_seic_GryphonSivMember_0DF34D059580239E01B9836890E43427" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_A13795820F26A55EC9B583689181B37F" xlink:to="loc_seic_GryphonSivMember_0DF34D059580239E01B9836890E43427" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AD8ECB352B6EB6B3CF74835ADF50DC2F" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_8E7E4A29FB13A513BBCF835ADF500F04" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AD8ECB352B6EB6B3CF74835ADF50DC2F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_150C7B146F86A4A9034E835ADF50E81D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AD8ECB352B6EB6B3CF74835ADF50DC2F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_150C7B146F86A4A9034E835ADF50E81D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_150C7B146F86A4A9034E835ADF50E81D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_AD8ECB352B6EB6B3CF74835ADF50DC2F" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_150C7B146F86A4A9034E835ADF50E81D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_C94FAB8C9E7635DB91BD835ADF5055D4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_150C7B146F86A4A9034E835ADF50E81D" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_C94FAB8C9E7635DB91BD835ADF5055D4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesRealizedGainLoss" xlink:label="loc_us-gaap_TradingSecuritiesRealizedGainLoss_8D1A2EFE0AD5B6F64E5E83689038300D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_61C13C82E0F06D951E96835ADF506CEA" xlink:to="loc_us-gaap_TradingSecuritiesRealizedGainLoss_8D1A2EFE0AD5B6F64E5E83689038300D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_3ABE54161B750199B898835ADF50D091" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_61C13C82E0F06D951E96835ADF506CEA" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_3ABE54161B750199B898835ADF50D091" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet_57566EAEB6D7BD1DDEFF835ADF50F936" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_61C13C82E0F06D951E96835ADF506CEA" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersNet_57566EAEB6D7BD1DDEFF835ADF50F936" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/FairValueMeasurementsReconciliationForAllAssetsAndLiabilitiesOfCompanyMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsLevel3Details" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_24EA1AB7E9879D284864F88254654925" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8D69802805C869A7EF72F8825465B10C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_24EA1AB7E9879D284864F88254654925" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8D69802805C869A7EF72F8825465B10C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueByAssetClassAxis" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_F163BDDDFA9C426001F5F88254656786" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationTable_8D69802805C869A7EF72F8825465B10C" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_F163BDDDFA9C426001F5F88254656786" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0059B171D7E50030AD1EF88254656982_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_F163BDDDFA9C426001F5F88254656786" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0059B171D7E50030AD1EF88254656982_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0059B171D7E50030AD1EF88254656982" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_F163BDDDFA9C426001F5F88254656786" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0059B171D7E50030AD1EF88254656982" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_24EA1AB7E9879D284864F88254654925" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_4D95757F35C76E5F891DF88254656ADA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_4D95757F35C76E5F891DF88254656ADA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_418F64FACC88D9AEACF3F88254655FF8" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_418F64FACC88D9AEACF3F88254655FF8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues_1FD9E293D44203F027E4F882546517F5" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetIssues_1FD9E293D44203F027E4F882546517F5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_E414008CF99E4BD6CDD0F8825465F45E" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_E414008CF99E4BD6CDD0F8825465F45E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_4CA5F3B62B4C645BAA87F8825465D2F6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales_4CA5F3B62B4C645BAA87F8825465D2F6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_2C5F36EADAD3BA714049F8825465C383" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInEarnings1_2C5F36EADAD3BA714049F8825465C383" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_9300F45D709D39CCE6FAF8825465890B" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss_9300F45D709D39CCE6FAF8825465890B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_6763CD9B06D1CDFDEDB2F8825465B14A" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_1FAF61B61C8A938D4998F8825465CC02" xlink:to="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetTransfersOutOfLevel3_6763CD9B06D1CDFDEDB2F8825465B14A" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/InvestmentInUnconsolidatedAffiliatesInvestmentInUnconsolidatedAffiliatesCondensedBalanceSheetsOfLsvDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_FE0D2443ED93670D03DA74A88E9DA3C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_FE0D2443ED93670D03DA74A88E9DA3C2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ED1576637B337E397EAA74A88E9D2133" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_FE0D2443ED93670D03DA74A88E9DA3C2" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ED1576637B337E397EAA74A88E9D2133" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E4A8C94D43B5056B841074A88E9D4762_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ED1576637B337E397EAA74A88E9D2133" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E4A8C94D43B5056B841074A88E9D4762_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E4A8C94D43B5056B841074A88E9D4762" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_ED1576637B337E397EAA74A88E9D2133" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E4A8C94D43B5056B841074A88E9D4762" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LSVAssetManagementMember" xlink:label="loc_seic_LSVAssetManagementMember_3C93C07BA52EC023944C74A88E9D0DB7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E4A8C94D43B5056B841074A88E9D4762" xlink:to="loc_seic_LSVAssetManagementMember_3C93C07BA52EC023944C74A88E9D0DB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets_0A7DAE8DE0B64AD7890974A88E9D2634" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentAssets_0A7DAE8DE0B64AD7890974A88E9D2634" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets_94E3D0AD5A1B387B3BE174A88E9D45DA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNoncurrentAssets_94E3D0AD5A1B387B3BE174A88E9D45DA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_11931123BDBDBB97EF3974A88E9D2986" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_11931123BDBDBB97EF3974A88E9D2986" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities_DED2B385A19B54E4D15774A88E9D9AFC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationCurrentLiabilities_DED2B385A19B54E4D15774A88E9D9AFC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_424A40D778C058460CDD74A88E9D9F0A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_424A40D778C058460CDD74A88E9D9F0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_EF5BE64970563DD2195474A88E9E749B" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_6E50008052E54F669E3F74A88E9D5B0C" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_EF5BE64970563DD2195474A88E9E749B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/InvestmentInUnconsolidatedAffiliatesInvestmentInUnconsolidatedAffiliatesCondensedStatementsOfOperationsOfLsvDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_E390BEF7134BB52AF77074A88EA787A7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_71675C01CDAB78D8416574A88EA7BC2A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_E390BEF7134BB52AF77074A88EA787A7" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_71675C01CDAB78D8416574A88EA7BC2A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_896E2412F0A9E95E989674A88EA79C46" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_71675C01CDAB78D8416574A88EA7BC2A" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_896E2412F0A9E95E989674A88EA79C46" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_B47E48E06BA9F5692B7674A88EA779D1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_896E2412F0A9E95E989674A88EA79C46" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_B47E48E06BA9F5692B7674A88EA779D1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_B47E48E06BA9F5692B7674A88EA779D1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_896E2412F0A9E95E989674A88EA79C46" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_B47E48E06BA9F5692B7674A88EA779D1" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LSVAssetManagementMember" xlink:label="loc_seic_LSVAssetManagementMember_5C5E33AA97136D88DD7E74A88EA7F493" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_B47E48E06BA9F5692B7674A88EA779D1" xlink:to="loc_seic_LSVAssetManagementMember_5C5E33AA97136D88DD7E74A88EA7F493" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_3234E099ECC2E4423BF574A88EA752BE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_E390BEF7134BB52AF77074A88EA787A7" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_3234E099ECC2E4423BF574A88EA752BE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss_902A96AE714975EE030574A88EA736A7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_E390BEF7134BB52AF77074A88EA787A7" xlink:to="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss_902A96AE714975EE030574A88EA736A7" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/InvestmentInUnconsolidatedAffiliatesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems" xlink:label="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_AD8D16B058EDED30618FF496DF877B4D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_AD8D16B058EDED30618FF496DF877B4D" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_EF35239D6C0AB047B0E1F496DF873D12" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_AD8D16B058EDED30618FF496DF877B4D" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_EF35239D6C0AB047B0E1F496DF873D12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E2E82B14A634C677DC23F496DF87C1FA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_EF35239D6C0AB047B0E1F496DF873D12" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E2E82B14A634C677DC23F496DF87C1FA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeNameDomain" xlink:label="loc_us-gaap_EquityMethodInvesteeNameDomain_E2E82B14A634C677DC23F496DF87C1FA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_EF35239D6C0AB047B0E1F496DF873D12" xlink:to="loc_us-gaap_EquityMethodInvesteeNameDomain_E2E82B14A634C677DC23F496DF87C1FA" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LSVAssetManagementMember" xlink:label="loc_seic_LSVAssetManagementMember_C1B0ADCB64889543A0EDF496DF87DFA6" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E2E82B14A634C677DC23F496DF87C1FA" xlink:to="loc_seic_LSVAssetManagementMember_C1B0ADCB64889543A0EDF496DF87DFA6" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_GaoFuMember" xlink:label="loc_seic_GaoFuMember_378694167F8673A8D5D7F496DF8700FD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvesteeNameDomain_E2E82B14A634C677DC23F496DF87C1FA" xlink:to="loc_seic_GaoFuMember_378694167F8673A8D5D7F496DF8700FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuaranteeObligationsByNatureAxis" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_93A53CBE64ED637A5DBFF496DF879BEA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_AD8D16B058EDED30618FF496DF877B4D" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_93A53CBE64ED637A5DBFF496DF879BEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_4927A153A7B3A367C730F496DF875BC2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_93A53CBE64ED637A5DBFF496DF879BEA" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_4927A153A7B3A367C730F496DF875BC2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuaranteeObligationsNatureDomain" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_4927A153A7B3A367C730F496DF875BC2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_93A53CBE64ED637A5DBFF496DF879BEA" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_4927A153A7B3A367C730F496DF875BC2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FinancialGuaranteeMember" xlink:label="loc_us-gaap_FinancialGuaranteeMember_087CF384E98FEE2C0D0FF496DF8717C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_4927A153A7B3A367C730F496DF875BC2" xlink:to="loc_us-gaap_FinancialGuaranteeMember_087CF384E98FEE2C0D0FF496DF8717C2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_56C3DE7452AF9960F7B9F496DF87650D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_AD8D16B058EDED30618FF496DF877B4D" xlink:to="loc_us-gaap_RangeAxis_56C3DE7452AF9960F7B9F496DF87650D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_5FE66F9D8DE41F93D66CF496DF87B4BB_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_56C3DE7452AF9960F7B9F496DF87650D" xlink:to="loc_us-gaap_RangeMember_5FE66F9D8DE41F93D66CF496DF87B4BB_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_5FE66F9D8DE41F93D66CF496DF87B4BB" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_56C3DE7452AF9960F7B9F496DF87650D" xlink:to="loc_us-gaap_RangeMember_5FE66F9D8DE41F93D66CF496DF87B4BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_0384BED11C1AAD6A8874F496DF878A83" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_5FE66F9D8DE41F93D66CF496DF87B4BB" xlink:to="loc_us-gaap_MaximumMember_0384BED11C1AAD6A8874F496DF878A83" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_A359A01130D7169ECE66F496DF87CA89" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_AD8D16B058EDED30618FF496DF877B4D" xlink:to="loc_dei_LegalEntityAxis_A359A01130D7169ECE66F496DF87CA89" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_A359A01130D7169ECE66F496DF87CA89" xlink:to="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_A359A01130D7169ECE66F496DF87CA89" xlink:to="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LsvEmployeeGroupMemberMember" xlink:label="loc_seic_LsvEmployeeGroupMemberMember_7EF21DCBAF7F85E1C866F496DF87EDB5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705" xlink:to="loc_seic_LsvEmployeeGroupMemberMember_7EF21DCBAF7F85E1C866F496DF87EDB5" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LsvEmployeeGroupIiMember" xlink:label="loc_seic_LsvEmployeeGroupIiMember_6AFA09A58A532317FA48F496DF871E07" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705" xlink:to="loc_seic_LsvEmployeeGroupIiMember_6AFA09A58A532317FA48F496DF871E07" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LsvEmployeeGroupIiiMember" xlink:label="loc_seic_LsvEmployeeGroupIiiMember_4EB9784B5B04EE86027DF496DF87B4DC" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705" xlink:to="loc_seic_LsvEmployeeGroupIiiMember_4EB9784B5B04EE86027DF496DF87B4DC" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LSVAssetManagementMember" xlink:label="loc_seic_LSVAssetManagementMember_A12EA8599CA6658F9178F496DF87CAC3" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_6F45715B4A77E72219AFF496DF875705" xlink:to="loc_seic_LSVAssetManagementMember_A12EA8599CA6658F9178F496DF87CAC3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_BA1732802773F44F2A32F496DF8757E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_BA1732802773F44F2A32F496DF8757E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestments" xlink:label="loc_us-gaap_EquityMethodInvestments_1FE03024EFD0CFEC4110F496DF878833" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_EquityMethodInvestments_1FE03024EFD0CFEC4110F496DF878833" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity" xlink:label="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_500F5102DD29DE9C5CD1F496DF8769A1" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_500F5102DD29DE9C5CD1F496DF8769A1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_F3DEBCF164C4F5EECD87F496DF870AC1" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_Goodwill_F3DEBCF164C4F5EECD87F496DF870AC1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_97B5EDD29ED2A3994481F496DF87B2C6" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_97B5EDD29ED2A3994481F496DF87B2C6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromContributionsFromAffiliates" xlink:label="loc_us-gaap_ProceedsFromContributionsFromAffiliates_2195CF214124DAF63D07F496DF87F200" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_ProceedsFromContributionsFromAffiliates_2195CF214124DAF63D07F496DF87F200" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuaranteeObligationsMaximumExposure" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_1682D7AAA9E68AE648FAF496DF878EA2" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_1682D7AAA9E68AE648FAF496DF878EA2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_BC3FFA3109D87CB527DDF496DF874370" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_BC3FFA3109D87CB527DDF496DF874370" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned" xlink:label="loc_us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned_A7667FD32CB893B78694F496DF871197" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned_A7667FD32CB893B78694F496DF871197" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_GuaranteeObligationsTerm" xlink:label="loc_us-gaap_GuaranteeObligationsTerm_4AC7A36B23D730FAE920F496DF8738A9" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_GuaranteeObligationsTerm_4AC7A36B23D730FAE920F496DF8738A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentPrincipal" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPaymentPrincipal_86F43C752544E3B15A3DF496DF8744B6" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_DebtInstrumentPeriodicPaymentPrincipal_86F43C752544E3B15A3DF496DF8744B6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LoansPayable" xlink:label="loc_us-gaap_LoansPayable_53AC8EFBDD7786BACB81F496DF87692E" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentsInAndAdvancesToAffiliatesLineItems_30AAC0934B6759611258F496DF876493" xlink:to="loc_us-gaap_LoansPayable_53AC8EFBDD7786BACB81F496DF87692E" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/LinesOfCreditDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_946A81212722C529F66774A88E2AD04E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_946A81212722C529F66774A88E2AD04E" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_58D75C324D2D40885C5C74A88E2ADFEA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_946A81212722C529F66774A88E2AD04E" xlink:to="loc_us-gaap_CreditFacilityAxis_58D75C324D2D40885C5C74A88E2ADFEA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_58D75C324D2D40885C5C74A88E2ADFEA" xlink:to="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_58D75C324D2D40885C5C74A88E2ADFEA" xlink:to="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_TwoThousandTwelveCreditFacilityMember" xlink:label="loc_seic_TwoThousandTwelveCreditFacilityMember_366C77FEAD2F13DEE76674A88E2A4EC0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2" xlink:to="loc_seic_TwoThousandTwelveCreditFacilityMember_366C77FEAD2F13DEE76674A88E2A4EC0" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_TwoThousandSevenCreditFacilityMemberMember" xlink:label="loc_seic_TwoThousandSevenCreditFacilityMemberMember_3ABFD8509E29E4CF491C74A88E2AAF06" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2" xlink:to="loc_seic_TwoThousandSevenCreditFacilityMemberMember_3ABFD8509E29E4CF491C74A88E2AAF06" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CanadianSubsidiaryMember" xlink:label="loc_seic_CanadianSubsidiaryMember_C170BED81902C3983BDD74A88E2A5826" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_26DD914047734A711B3E74A88E2A59C2" xlink:to="loc_seic_CanadianSubsidiaryMember_C170BED81902C3983BDD74A88E2A5826" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityDescription" xlink:label="loc_us-gaap_LineOfCreditFacilityDescription_77AAA5F731C89F06689874A88E2B0837" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityDescription_77AAA5F731C89F06689874A88E2B0837" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_7579A62B770D5F12B19674A88E2B09FD" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_7579A62B770D5F12B19674A88E2B09FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationDate1" xlink:label="loc_us-gaap_LineOfCreditFacilityExpirationDate1_6B22BD72DE9B477B5CF574A88E2B900B" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityExpirationDate1_6B22BD72DE9B477B5CF574A88E2B900B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_F9550F9412B3F740217674A88E2BF59F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_F9550F9412B3F740217674A88E2BF59F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ProceedsFromLinesOfCredit" xlink:label="loc_us-gaap_ProceedsFromLinesOfCredit_379CA99B83223A61086C74A88E2BB47A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_ProceedsFromLinesOfCredit_379CA99B83223A61086C74A88E2BB47A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_A8043DC762182653EF2D74A88E2BF7C5" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_A8043DC762182653EF2D74A88E2BF7C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityIncreaseDecreaseOtherNet" xlink:label="loc_us-gaap_LineOfCreditFacilityIncreaseDecreaseOtherNet_B0FC35A76A20AEBA420B74A88E2B1FF0" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityIncreaseDecreaseOtherNet_B0FC35A76A20AEBA420B74A88E2B1FF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityAmountOutstanding" xlink:label="loc_us-gaap_LineOfCreditFacilityAmountOutstanding_0B4639F826F265CB1B4974A88E2BABAC" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityAmountOutstanding_0B4639F826F265CB1B4974A88E2BABAC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityDecreaseRepayments" xlink:label="loc_us-gaap_LineOfCreditFacilityDecreaseRepayments_29DDDCDE3204EA95D03074A88E2BA315" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityDecreaseRepayments_29DDDCDE3204EA95D03074A88E2BA315" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LineOfCreditFacilityInterestRateDuringPeriod" xlink:label="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_053A02307E5A891933B574A88E2B23E4" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_LineOfCreditFacilityInterestRateDuringPeriod_053A02307E5A891933B574A88E2B23E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_InterestExpense" xlink:label="loc_us-gaap_InterestExpense_442ABD414D5F7E906BFE74A88E2B2DF1" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_842E57DE3A6FE8EC392674A88E2B5789" xlink:to="loc_us-gaap_InterestExpense_442ABD414D5F7E906BFE74A88E2B2DF1" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/MarketableSecuritiesInvestmentsAvailableForSaleDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_287ACF7DC4588F576266217B3439542C" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_5FEDA5D716E1E8029518217B343987E3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_287ACF7DC4588F576266217B3439542C" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_5FEDA5D716E1E8029518217B343987E3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_D604CCCC6B5166768F04217B34390A9B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_5FEDA5D716E1E8029518217B343987E3" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_D604CCCC6B5166768F04217B34390A9B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_D604CCCC6B5166768F04217B34390A9B" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_D604CCCC6B5166768F04217B34390A9B" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SeiSponsoredMutualFundsMember" xlink:label="loc_seic_SeiSponsoredMutualFundsMember_3F117D02A1C4A4900A88217B3439BD28" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848" xlink:to="loc_seic_SeiSponsoredMutualFundsMember_3F117D02A1C4A4900A88217B3439BD28" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityFundsMember" xlink:label="loc_us-gaap_EquityFundsMember_A9DBDD7B91F2EB010430217B3439281E" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848" xlink:to="loc_us-gaap_EquityFundsMember_A9DBDD7B91F2EB010430217B3439281E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DebtSecuritiesMember" xlink:label="loc_us-gaap_DebtSecuritiesMember_8670DBB8F6F6F92589FB217B3439CB52" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_D54279BB507573ABA9B0217B3439E848" xlink:to="loc_us-gaap_DebtSecuritiesMember_8670DBB8F6F6F92589FB217B3439CB52" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesAmortizedCost_43C5D2CA192387AA75BD217B3439E6E2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_287ACF7DC4588F576266217B3439542C" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesAmortizedCost_43C5D2CA192387AA75BD217B3439E6E2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain_455F4AE6D4DF31951307217B3439AC92" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_287ACF7DC4588F576266217B3439542C" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesGrossUnrealizedGain_455F4AE6D4DF31951307217B3439AC92" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1_A5D6DC2DED050342AE22217B3439C9F7" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_287ACF7DC4588F576266217B3439542C" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLosses1_A5D6DC2DED050342AE22217B3439C9F7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesNoncurrent" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesNoncurrent_0C8917558508186A3936217B3439DBC9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_287ACF7DC4588F576266217B3439542C" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesNoncurrent_0C8917558508186A3936217B3439DBC9" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/MarketableSecuritiesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfInvestmentsLineItems" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfInvestmentsTable" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_D00305E46087C32F59F3F39167A2698B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_D00305E46087C32F59F3F39167A2698B" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_547F4881E741358038DDF39167A27945" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_D00305E46087C32F59F3F39167A2698B" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_547F4881E741358038DDF39167A27945" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_547F4881E741358038DDF39167A27945" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_547F4881E741358038DDF39167A27945" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_03B0D451835B3E028C60F39167A20783" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:to="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_03B0D451835B3E028C60F39167A20783" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuritiesAssetsMember" xlink:label="loc_us-gaap_SecuritiesAssetsMember_E40CCD14B95B6F62EAA5F39167A2C2CB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:to="loc_us-gaap_SecuritiesAssetsMember_E40CCD14B95B6F62EAA5F39167A2C2CB" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_GryphonSivMember" xlink:label="loc_seic_GryphonSivMember_BB8FF1088443146C84C8F39167A284E4" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:to="loc_seic_GryphonSivMember_BB8FF1088443146C84C8F39167A284E4" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_StanfieldVictoriaSivMember" xlink:label="loc_seic_StanfieldVictoriaSivMember_BC322B4C990FAB443A24F39167A2B34C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:to="loc_seic_StanfieldVictoriaSivMember_BC322B4C990FAB443A24F39167A2B34C" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LsvSponsoredMutualFundsMember" xlink:label="loc_seic_LsvSponsoredMutualFundsMember_BCCFD0B3BD3AE1172672F39167A21A0A" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_2B271C09BFE96EE404AAF39167A29A3D" xlink:to="loc_seic_LsvSponsoredMutualFundsMember_BCCFD0B3BD3AE1172672F39167A21A0A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_7A6E09B95B1D404BC754F39167A29423" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_D00305E46087C32F59F3F39167A2698B" xlink:to="loc_dei_LegalEntityAxis_7A6E09B95B1D404BC754F39167A29423" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_96247A9331F81E9F7794F39167A22F3E_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_7A6E09B95B1D404BC754F39167A29423" xlink:to="loc_dei_EntityDomain_96247A9331F81E9F7794F39167A22F3E_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_96247A9331F81E9F7794F39167A22F3E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_7A6E09B95B1D404BC754F39167A29423" xlink:to="loc_dei_EntityDomain_96247A9331F81E9F7794F39167A22F3E" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SeiPrivateTrustCompanyMember" xlink:label="loc_seic_SeiPrivateTrustCompanyMember_9F15F7B10527FDAD435AF39167A268A5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_96247A9331F81E9F7794F39167A22F3E" xlink:to="loc_seic_SeiPrivateTrustCompanyMember_9F15F7B10527FDAD435AF39167A268A5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_747C0646C6C2E47C43AEF39167A2A2E6" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_D00305E46087C32F59F3F39167A2698B" xlink:to="loc_us-gaap_RangeAxis_747C0646C6C2E47C43AEF39167A2A2E6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_433BDB0FBF54DCBBBD5FF39167A2AFAA_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_747C0646C6C2E47C43AEF39167A2A2E6" xlink:to="loc_us-gaap_RangeMember_433BDB0FBF54DCBBBD5FF39167A2AFAA_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_433BDB0FBF54DCBBBD5FF39167A2AFAA" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_747C0646C6C2E47C43AEF39167A2A2E6" xlink:to="loc_us-gaap_RangeMember_433BDB0FBF54DCBBBD5FF39167A2AFAA" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_57A8162F406E8ED0D51AF39167A25C1D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_433BDB0FBF54DCBBBD5FF39167A2AFAA" xlink:to="loc_us-gaap_MinimumMember_57A8162F406E8ED0D51AF39167A25C1D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_F11F3479A9BC9D00ABC5F39167A2927D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_433BDB0FBF54DCBBBD5FF39167A2AFAA" xlink:to="loc_us-gaap_MaximumMember_F11F3479A9BC9D00ABC5F39167A2927D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_99F9D8C89B0B18A3344FF39167A292A9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax_99F9D8C89B0B18A3344FF39167A292A9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesIncomeTaxExpenseOnChangeInUnrealizedHoldingGainOrLoss" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesIncomeTaxExpenseOnChangeInUnrealizedHoldingGainOrLoss_350E903A0C1C074EF1F3F39167A2214D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesIncomeTaxExpenseOnChangeInUnrealizedHoldingGainOrLoss_350E903A0C1C074EF1F3F39167A2214D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_FCF0BD3C8E3B567E9A19F39167A20F4A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_FCF0BD3C8E3B567E9A19F39167A20F4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AvailableforsaleSecuritiesDebtMaturitiesDate" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesDebtMaturitiesDate_41E073F8C393CB2EB40AF39167A28CB9" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_AvailableforsaleSecuritiesDebtMaturitiesDate_41E073F8C393CB2EB40AF39167A28CB9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesRealizedGain" xlink:label="loc_us-gaap_TradingSecuritiesRealizedGain_9D3826E2B01FB968702CF39167A27596" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_TradingSecuritiesRealizedGain_9D3826E2B01FB968702CF39167A27596" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_GainsFromCashPaymentsReceivedFromSivSecurities" xlink:label="loc_seic_GainsFromCashPaymentsReceivedFromSivSecurities_42B071093BFEAC4A71E1F39167A21F6F" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_seic_GainsFromCashPaymentsReceivedFromSivSecurities_42B071093BFEAC4A71E1F39167A21F6F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_UnrealizedGainLossOnSecurities" xlink:label="loc_us-gaap_UnrealizedGainLossOnSecurities_738E2B57B2D52CD19B32F39167A209A4" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_UnrealizedGainLossOnSecurities_738E2B57B2D52CD19B32F39167A209A4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesRealizedGainLoss" xlink:label="loc_us-gaap_TradingSecuritiesRealizedGainLoss_3313939135FB3C711FDBF39167A2A6D1" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_TradingSecuritiesRealizedGainLoss_3313939135FB3C711FDBF39167A2A6D1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue" xlink:label="loc_us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue_006350C11CBB71176651F39167A2CE12" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_FinancialInstrumentsOwnedUSGovernmentAndAgencyObligationsAtFairValue_006350C11CBB71176651F39167A2CE12" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RealizedInvestmentGainsLosses" xlink:label="loc_us-gaap_RealizedInvestmentGainsLosses_0BBCCC2F0D6F1130BF82F39167A27F0F" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_E2929C074DB3D88F8549F39167A234D5" xlink:to="loc_us-gaap_RealizedInvestmentGainsLosses_0BBCCC2F0D6F1130BF82F39167A27F0F" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/MarketableSecuritiesTradingSecuritiesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems" xlink:label="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_1AAF5D133DEF8ABAEC92D53A634954A9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable" xlink:label="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable_960475629FF24E41413AD53A6349C7E7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_1AAF5D133DEF8ABAEC92D53A634954A9" xlink:to="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable_960475629FF24E41413AD53A6349C7E7" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_B54D23259E987B415454D53A6349EF18" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsTable_960475629FF24E41413AD53A6349C7E7" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_B54D23259E987B415454D53A6349EF18" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_B54D23259E987B415454D53A6349EF18" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_B54D23259E987B415454D53A6349EF18" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuritiesAssetsMember" xlink:label="loc_us-gaap_SecuritiesAssetsMember_0AB2ABE976DF989E6AC7D53A6349346A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B" xlink:to="loc_us-gaap_SecuritiesAssetsMember_0AB2ABE976DF989E6AC7D53A6349346A" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LsvSponsoredMutualFundsMember" xlink:label="loc_seic_LsvSponsoredMutualFundsMember_91A6FBBD5D456C397082D53A63492DE4" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B" xlink:to="loc_seic_LsvSponsoredMutualFundsMember_91A6FBBD5D456C397082D53A63492DE4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherInvestmentsMember" xlink:label="loc_us-gaap_OtherInvestmentsMember_CAF0D71D2060E98F9820D53A63499D37" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_F192F839C9A654E13A67D53A6349DD0B" xlink:to="loc_us-gaap_OtherInvestmentsMember_CAF0D71D2060E98F9820D53A63499D37" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesCost" xlink:label="loc_us-gaap_TradingSecuritiesCost_E73DFB00BD3AE5E18990D53A63493266" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_1AAF5D133DEF8ABAEC92D53A634954A9" xlink:to="loc_us-gaap_TradingSecuritiesCost_E73DFB00BD3AE5E18990D53A63493266" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesUnrealizedHoldingGain" xlink:label="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGain_44D7F670B50DDBF734F6D53A63498BEF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_1AAF5D133DEF8ABAEC92D53A634954A9" xlink:to="loc_us-gaap_TradingSecuritiesUnrealizedHoldingGain_44D7F670B50DDBF734F6D53A63498BEF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesUnrealizedHoldingLoss" xlink:label="loc_us-gaap_TradingSecuritiesUnrealizedHoldingLoss_0C3AA0500D7EC0D7CA4DD53A6349BB3F" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_1AAF5D133DEF8ABAEC92D53A634954A9" xlink:to="loc_us-gaap_TradingSecuritiesUnrealizedHoldingLoss_0C3AA0500D7EC0D7CA4DD53A6349BB3F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherMarketableSecuritiesNoncurrent" xlink:label="loc_us-gaap_OtherMarketableSecuritiesNoncurrent_07F16767FFA079390838D53A63490F67" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfTradingSecuritiesAndOtherTradingAssetsLineItems_1AAF5D133DEF8ABAEC92D53A634954A9" xlink:to="loc_us-gaap_OtherMarketableSecuritiesNoncurrent_07F16767FFA079390838D53A63490F67" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/QuarterlyFinancialDataSivRelatedGainsLossesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_7AE5B68DBF7794D15580F3314F8215CF" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_7AE5B68DBF7794D15580F3314F8215CF" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_1A4193F37CD1FED53936F3314F82A586" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_7AE5B68DBF7794D15580F3314F8215CF" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_1A4193F37CD1FED53936F3314F82A586" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_0342A617C0EA16C51C91F3314F820F8B_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_1A4193F37CD1FED53936F3314F82A586" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_0342A617C0EA16C51C91F3314F820F8B_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain" xlink:label="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_0342A617C0EA16C51C91F3314F820F8B" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis_1A4193F37CD1FED53936F3314F82A586" xlink:to="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_0342A617C0EA16C51C91F3314F820F8B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SecuritiesAssetsMember" xlink:label="loc_us-gaap_SecuritiesAssetsMember_B47396A98FA2FFC4D8A9F3314F82AE6C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MajorTypesOfDebtAndEquitySecuritiesDomain_0342A617C0EA16C51C91F3314F820F8B" xlink:to="loc_us-gaap_SecuritiesAssetsMember_B47396A98FA2FFC4D8A9F3314F82AE6C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Revenues" xlink:label="loc_us-gaap_Revenues_0114C50CB9D0CEE959F4F3314F829668" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_Revenues_0114C50CB9D0CEE959F4F3314F829668" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_D3164C704D03ACD8700EF3314F823F36" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_D3164C704D03ACD8700EF3314F823F36" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_F4D0CD742830CE992975F3314F82658D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_NetIncomeLoss_F4D0CD742830CE992975F3314F82658D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_862E096DA2092B76094EF3314F829A6D" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_EarningsPerShareBasic_862E096DA2092B76094EF3314F829A6D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_3E55632A2A6DF9AE3E3EF3314F82BF34" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_EarningsPerShareDiluted_3E55632A2A6DF9AE3E3EF3314F82BF34" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_4B8262951CDCA064AABCF3314F8258A3" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_4B8262951CDCA064AABCF3314F8258A3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_TradingSecuritiesRealizedGainLoss" xlink:label="loc_us-gaap_TradingSecuritiesRealizedGainLoss_E70C621963FF17E819E1F3314F824AD3" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_DCF6172DCE1661029520F3314F82C184" xlink:to="loc_us-gaap_TradingSecuritiesRealizedGainLoss_E70C621963FF17E819E1F3314F824AD3" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/SaleOfSeiAssetKoreaSaleOfSeiAssetKoreaNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_9B93803C38C8E024E6D5F30E2F66B76C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_9B93803C38C8E024E6D5F30E2F66B76C" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0D34E4293984BCD20200F30E2F6621E4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_9B93803C38C8E024E6D5F30E2F66B76C" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0D34E4293984BCD20200F30E2F6621E4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_46285724B62838D5D155F30E2F66BE22_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0D34E4293984BCD20200F30E2F6621E4" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_46285724B62838D5D155F30E2F66BE22_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_46285724B62838D5D155F30E2F66BE22" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0D34E4293984BCD20200F30E2F6621E4" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_46285724B62838D5D155F30E2F66BE22" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SeiAssetKoreaCoLtdMember" xlink:label="loc_seic_SeiAssetKoreaCoLtdMember_442AB164B4F887A188EFF30E2F668DF0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_46285724B62838D5D155F30E2F66BE22" xlink:to="loc_seic_SeiAssetKoreaCoLtdMember_442AB164B4F887A188EFF30E2F668DF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SaleOfStockPercentageOfOwnershipBeforeTransaction" xlink:label="loc_us-gaap_SaleOfStockPercentageOfOwnershipBeforeTransaction_CEE8D0C5175CA2BE3234F30E2F662561" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:to="loc_us-gaap_SaleOfStockPercentageOfOwnershipBeforeTransaction_CEE8D0C5175CA2BE3234F30E2F662561" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationSegmentThatIncludesDisposalGroup" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationSegmentThatIncludesDisposalGroup_F1D3FA1BBFAEE2FA093BF316E3B84557" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationSegmentThatIncludesDisposalGroup_F1D3FA1BBFAEE2FA093BF316E3B84557" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_CE055C6FB9340CAC314EF30E2F66E2AD" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:to="loc_us-gaap_Assets_CE055C6FB9340CAC314EF30E2F66E2AD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_3422C2BE3080D29C7064F30E2F66839F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_3422C2BE3080D29C7064F30E2F66839F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AccruedIncomeTaxesNoncurrent" xlink:label="loc_us-gaap_AccruedIncomeTaxesNoncurrent_52D7F19A434F1B762B9AF30E2F66223B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_DF84DC3178BBEFC7EEC4F30E2F66966B" xlink:to="loc_us-gaap_AccruedIncomeTaxesNoncurrent_52D7F19A434F1B762B9AF30E2F66223B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/ScheduleIiValuationAndQualifyingAccountsAndReservesDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAndQualifyingAccountsDisclosureLineItems" xlink:label="loc_us-gaap_ValuationAndQualifyingAccountsDisclosureLineItems_BED1C6E90033F768FC2DF338182101D1" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAndQualifyingAccountsDisclosureTable" xlink:label="loc_us-gaap_ValuationAndQualifyingAccountsDisclosureTable_4D22CAA7B5AEEDA185AAF33818212601" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ValuationAndQualifyingAccountsDisclosureLineItems_BED1C6E90033F768FC2DF338182101D1" xlink:to="loc_us-gaap_ValuationAndQualifyingAccountsDisclosureTable_4D22CAA7B5AEEDA185AAF33818212601" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_50C2ED9504C2ACFD90CEF3381821A0F4" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ValuationAndQualifyingAccountsDisclosureTable_4D22CAA7B5AEEDA185AAF33818212601" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_50C2ED9504C2ACFD90CEF3381821A0F4" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_7C71BD849434E4C402B5F3381821270D_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_50C2ED9504C2ACFD90CEF3381821A0F4" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_7C71BD849434E4C402B5F3381821270D_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDomain" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_7C71BD849434E4C402B5F3381821270D" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_50C2ED9504C2ACFD90CEF3381821A0F4" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_7C71BD849434E4C402B5F3381821270D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsMember" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsMember_8E3891163906C949CE3EF3381821F025" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_7C71BD849434E4C402B5F3381821270D" xlink:to="loc_us-gaap_AllowanceForDoubtfulAccountsMember_8E3891163906C949CE3EF3381821F025" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_6F5F955565E48BF8DD14F33818219CFE" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_7C71BD849434E4C402B5F3381821270D" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_6F5F955565E48BF8DD14F33818219CFE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_1A8A1A023183CA4C93AAF33EAA6F42EE" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAndQualifyingAccountsDisclosureLineItems_BED1C6E90033F768FC2DF338182101D1" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_1A8A1A023183CA4C93AAF33EAA6F42EE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesBalance" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_90DBB86A46C48FDDEF07F3381821618A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_1A8A1A023183CA4C93AAF33EAA6F42EE" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_90DBB86A46C48FDDEF07F3381821618A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_72A9CC140B0E314CC501F3381821E142" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_1A8A1A023183CA4C93AAF33EAA6F42EE" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_72A9CC140B0E314CC501F3381821E142" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_D6AAE91176F4182F984AF33818213CBB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_1A8A1A023183CA4C93AAF33EAA6F42EE" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_D6AAE91176F4182F984AF33818213CBB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ValuationAllowancesAndReservesDeductions" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDeductions_C91DC9F0CE6F4D09E7CCF338182180B4" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_1A8A1A023183CA4C93AAF33EAA6F42EE" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDeductions_C91DC9F0CE6F4D09E7CCF338182180B4" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/ShareholdersEquityNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5A93EF92D1318ADEDF74FE07BE0F86C2" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5A93EF92D1318ADEDF74FE07BE0F86C2" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_032996B11AA3D1966B08FE07BE0F862E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5A93EF92D1318ADEDF74FE07BE0F86C2" xlink:to="loc_us-gaap_PlanNameAxis_032996B11AA3D1966B08FE07BE0F862E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_48404AB6D56FF29CBFE4FE07BE0FA0F7_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_032996B11AA3D1966B08FE07BE0F862E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_48404AB6D56FF29CBFE4FE07BE0FA0F7_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_48404AB6D56FF29CBFE4FE07BE0FA0F7" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_032996B11AA3D1966B08FE07BE0F862E" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_48404AB6D56FF29CBFE4FE07BE0FA0F7" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_TwoThousandSevenPlanMember" xlink:label="loc_seic_TwoThousandSevenPlanMember_AB85E49CC53C68362AD6FE07BE0F3190" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_48404AB6D56FF29CBFE4FE07BE0FA0F7" xlink:to="loc_seic_TwoThousandSevenPlanMember_AB85E49CC53C68362AD6FE07BE0F3190" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_A1998PlanMember" xlink:label="loc_seic_A1998PlanMember_F36D2F158E453E3EF3F4FE07BE0F345B" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_48404AB6D56FF29CBFE4FE07BE0FA0F7" xlink:to="loc_seic_A1998PlanMember_F36D2F158E453E3EF3F4FE07BE0F345B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_0027E1D727B9C0CC3B86FE07BE0F58BF" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5A93EF92D1318ADEDF74FE07BE0F86C2" xlink:to="loc_us-gaap_RangeAxis_0027E1D727B9C0CC3B86FE07BE0F58BF" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_04DEED9CBCE0C40409EAFE07BE0F4DDD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_0027E1D727B9C0CC3B86FE07BE0F58BF" xlink:to="loc_us-gaap_RangeMember_04DEED9CBCE0C40409EAFE07BE0F4DDD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_04DEED9CBCE0C40409EAFE07BE0F4DDD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_0027E1D727B9C0CC3B86FE07BE0F58BF" xlink:to="loc_us-gaap_RangeMember_04DEED9CBCE0C40409EAFE07BE0F4DDD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_F15453F40D427947E8F1FE07BE0F18E5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_04DEED9CBCE0C40409EAFE07BE0F4DDD" xlink:to="loc_us-gaap_MinimumMember_F15453F40D427947E8F1FE07BE0F18E5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_A925CA88D94FC9EDCA81FE07BE0F186A" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_04DEED9CBCE0C40409EAFE07BE0F4DDD" xlink:to="loc_us-gaap_MaximumMember_A925CA88D94FC9EDCA81FE07BE0F186A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DividendsAxis" xlink:label="loc_us-gaap_DividendsAxis_9787C4E540E3DD7A2C36FE07BE0F26BB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_5A93EF92D1318ADEDF74FE07BE0F86C2" xlink:to="loc_us-gaap_DividendsAxis_9787C4E540E3DD7A2C36FE07BE0F26BB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DividendsDomain" xlink:label="loc_us-gaap_DividendsDomain_5FEE741C49A9156FA725FE07BE0F14C1_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DividendsAxis_9787C4E540E3DD7A2C36FE07BE0F26BB" xlink:to="loc_us-gaap_DividendsDomain_5FEE741C49A9156FA725FE07BE0F14C1_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DividendsDomain" xlink:label="loc_us-gaap_DividendsDomain_5FEE741C49A9156FA725FE07BE0F14C1" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DividendsAxis_9787C4E540E3DD7A2C36FE07BE0F26BB" xlink:to="loc_us-gaap_DividendsDomain_5FEE741C49A9156FA725FE07BE0F14C1" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_InterimCashDividendsMember" xlink:label="loc_seic_InterimCashDividendsMember_6CC78554A3DB7853BFBDFE07BE0FB234" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_5FEE741C49A9156FA725FE07BE0F14C1" xlink:to="loc_seic_InterimCashDividendsMember_6CC78554A3DB7853BFBDFE07BE0FB234" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_FinalCashDividendsMember" xlink:label="loc_seic_FinalCashDividendsMember_809B1CF6C6AE0913F498FE07BE0FBC0D" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_5FEE741C49A9156FA725FE07BE0F14C1" xlink:to="loc_seic_FinalCashDividendsMember_809B1CF6C6AE0913F498FE07BE0FBC0D" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfActivePlans" xlink:label="loc_seic_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfActivePlans_4E657C56297C311E3448FE07BE0FD205" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfActivePlans_4E657C56297C311E3448FE07BE0FD205" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_692EB3D34FD91A33BE4DFE07BE0FCF97" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_692EB3D34FD91A33BE4DFE07BE0FCF97" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_VestingRateWhenSpecifiedDilutedEarningsPerShareTargetsAreAchieved" xlink:label="loc_seic_VestingRateWhenSpecifiedDilutedEarningsPerShareTargetsAreAchieved_0DD4A3DAC4A91228E72FFE07BE0F4469" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_VestingRateWhenSpecifiedDilutedEarningsPerShareTargetsAreAchieved_0DD4A3DAC4A91228E72FFE07BE0F4469" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_VestingRateHigherSpecifiedDilutedEarningsPerShareTargetsAreAchieved" xlink:label="loc_seic_VestingRateHigherSpecifiedDilutedEarningsPerShareTargetsAreAchieved_D949D733BE23CD3B025FFE07BE0F6F0B" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_VestingRateHigherSpecifiedDilutedEarningsPerShareTargetsAreAchieved_D949D733BE23CD3B025FFE07BE0F6F0B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_470EC3DBFACD2BC55CCAFE07BE0FBDC8" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_470EC3DBFACD2BC55CCAFE07BE0FBDC8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsed" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsed_C1F23C147155FBF46F1AFE07BE0F6406" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsMethodUsed_C1F23C147155FBF46F1AFE07BE0F6406" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_BA89F1749FE56E376CB8FE07BE0F4776" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_BA89F1749FE56E376CB8FE07BE0F4776" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_ChangeInManagementEstimateOfStockBasedCompensationExpenseAmortization" xlink:label="loc_seic_ChangeInManagementEstimateOfStockBasedCompensationExpenseAmortization_200313761B5B4CD01BDCFE07BE0FD7C7" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_ChangeInManagementEstimateOfStockBasedCompensationExpenseAmortization_200313761B5B4CD01BDCFE07BE0FD7C7" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_AmountOfPreviouslyRecognizedStockBasedCompensationCostsReversed" xlink:label="loc_seic_AmountOfPreviouslyRecognizedStockBasedCompensationCostsReversed_3F3DF3D2687296B809F3FE07BE0F272E" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_AmountOfPreviouslyRecognizedStockBasedCompensationCostsReversed_3F3DF3D2687296B809F3FE07BE0F272E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_7DD5D202B721F75A01A3FE07BE0FDE58" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_7DD5D202B721F75A01A3FE07BE0FDE58" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_9BDF5DB0651AA9ACAECDFE07BE0FE76D" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_9BDF5DB0651AA9ACAECDFE07BE0FE76D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate_9F55EB13F357C09FD728FE07BE0F239C" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate_9F55EB13F357C09FD728FE07BE0F239C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_5795CC903815BE77B4D3FE07BE0F1E27" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_5795CC903815BE77B4D3FE07BE0F1E27" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_A5089934CA304FED7061FE07BE0F38CE" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_A5089934CA304FED7061FE07BE0F38CE" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_906DB2C46E290F675EF2FE07BE0F501E" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_906DB2C46E290F675EF2FE07BE0F501E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_65E2409DC8FF8FFECFBBFE07BE0F633B" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_65E2409DC8FF8FFECFBBFE07BE0F633B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharePrice" xlink:label="loc_us-gaap_SharePrice_A0FEC8A157F370CAE987FE07BE0F6959" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_SharePrice_A0FEC8A157F370CAE987FE07BE0F6959" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_A961BE3FB15112229F01FE07BE0F52E3" xlink:type="locator" />
    <link:definitionArc order="18" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPriceOfferingDate_A961BE3FB15112229F01FE07BE0F52E3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_3D341AD0C418A23ED841FE07BE0F1D44" xlink:type="locator" />
    <link:definitionArc order="19" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_3D341AD0C418A23ED841FE07BE0F1D44" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_718F04881D1E5B14566CFE07BE0FD6B7" xlink:type="locator" />
    <link:definitionArc order="20" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_718F04881D1E5B14566CFE07BE0FD6B7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense" xlink:label="loc_us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense_C8E1DC04B3B1A3642864FE07BE0FBD5F" xlink:type="locator" />
    <link:definitionArc order="21" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_EmployeeStockOwnershipPlanESOPCompensationExpense_C8E1DC04B3B1A3642864FE07BE0FBD5F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount_FA244287F9CA973829B3FE07BE0F3CCF" xlink:type="locator" />
    <link:definitionArc order="22" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount_FA244287F9CA973829B3FE07BE0F3CCF" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_RightsReceivedByCommonShareholderForEachCommonShareOutstandingRights" xlink:label="loc_seic_RightsReceivedByCommonShareholderForEachCommonShareOutstandingRights_B586977BA47622A65F2CFE07BE0F651F" xlink:type="locator" />
    <link:definitionArc order="23" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_RightsReceivedByCommonShareholderForEachCommonShareOutstandingRights_B586977BA47622A65F2CFE07BE0F651F" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_6B72370678F820ED1123FE07BE0F111E" xlink:type="locator" />
    <link:definitionArc order="24" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_6B72370678F820ED1123FE07BE0F111E" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SecuritiesAndAssetsOfEquivalentValuePurchasePricePerUnit" xlink:label="loc_seic_SecuritiesAndAssetsOfEquivalentValuePurchasePricePerUnit_A9A5D866FCDD3829BA32FE07BE0F56C0" xlink:type="locator" />
    <link:definitionArc order="25" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_SecuritiesAndAssetsOfEquivalentValuePurchasePricePerUnit_A9A5D866FCDD3829BA32FE07BE0F56C0" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_NumberOfDaysRightsBecomeExercisableFollowingPublicAnnouncement" xlink:label="loc_seic_NumberOfDaysRightsBecomeExercisableFollowingPublicAnnouncement_BA89C3A1277BCA597587FE07BE0F7865" xlink:type="locator" />
    <link:definitionArc order="26" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_NumberOfDaysRightsBecomeExercisableFollowingPublicAnnouncement_BA89C3A1277BCA597587FE07BE0F7865" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_LeveragedBuyoutContinuingOwnershipInterestByContinuingStockholders" xlink:label="loc_us-gaap_LeveragedBuyoutContinuingOwnershipInterestByContinuingStockholders_E1DF83B2AE504A798CF8FE07BE0F1D47" xlink:type="locator" />
    <link:definitionArc order="27" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_LeveragedBuyoutContinuingOwnershipInterestByContinuingStockholders_E1DF83B2AE504A798CF8FE07BE0F1D47" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_HoldersOtherThanAcquiringPersonRightToPurchaseOfCommonStockUponExerciseOfRights" xlink:label="loc_seic_HoldersOtherThanAcquiringPersonRightToPurchaseOfCommonStockUponExerciseOfRights_5D82CAF8071D309B442BFE07BE0F7B89" xlink:type="locator" />
    <link:definitionArc order="28" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_HoldersOtherThanAcquiringPersonRightToPurchaseOfCommonStockUponExerciseOfRights_5D82CAF8071D309B442BFE07BE0F7B89" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CommonSharesReceivedByHoldersUponSurrenderOfRightsPercentage" xlink:label="loc_seic_CommonSharesReceivedByHoldersUponSurrenderOfRightsPercentage_6DECDB60A3697E9D8204FE07BE0FC5D5" xlink:type="locator" />
    <link:definitionArc order="29" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_CommonSharesReceivedByHoldersUponSurrenderOfRightsPercentage_6DECDB60A3697E9D8204FE07BE0FC5D5" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_RightsNonVotingRedeemableDays" xlink:label="loc_seic_RightsNonVotingRedeemableDays_B61BDD30ACD3C9485281FE07BE0F1E5B" xlink:type="locator" />
    <link:definitionArc order="30" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_RightsNonVotingRedeemableDays_B61BDD30ACD3C9485281FE07BE0F1E5B" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_RightRedeemablePricePerRight" xlink:label="loc_seic_RightRedeemablePricePerRight_A8B64C115E3094058627FE07BE0FA659" xlink:type="locator" />
    <link:definitionArc order="31" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_seic_RightRedeemablePricePerRight_A8B64C115E3094058627FE07BE0FA659" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_F60155866B57C12BC292FE07BE0F38F8" xlink:type="locator" />
    <link:definitionArc order="32" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_F60155866B57C12BC292FE07BE0F38F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_DividendsCommonStock" xlink:label="loc_us-gaap_DividendsCommonStock_E341156EB16F1F363329FE07BE0F69D5" xlink:type="locator" />
    <link:definitionArc order="33" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_95059C64634F11081D8CFE07BE0FD759" xlink:to="loc_us-gaap_DividendsCommonStock_E341156EB16F1F363329FE07BE0F69D5" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/ShareholdersEquityScheduleOfReconciliationOfNoncontrollingInterestOnConsolidatedBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinorityInterestLineItems" xlink:label="loc_us-gaap_MinorityInterestLineItems_74FEECDB5795F8777382F985A86C231B" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinorityInterestTable" xlink:label="loc_us-gaap_MinorityInterestTable_A3605F4F4762CCE4F82AF985A86CB528" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_MinorityInterestLineItems_74FEECDB5795F8777382F985A86C231B" xlink:to="loc_us-gaap_MinorityInterestTable_A3605F4F4762CCE4F82AF985A86CB528" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_6AF8788B65B01CDA8C72F985A86CC94C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_A3605F4F4762CCE4F82AF985A86CB528" xlink:to="loc_dei_LegalEntityAxis_6AF8788B65B01CDA8C72F985A86CC94C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_6AF8788B65B01CDA8C72F985A86CC94C" xlink:to="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_6AF8788B65B01CDA8C72F985A86CC94C" xlink:to="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_53E0B8F347194DCCF620F985A86C6A69" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09" xlink:to="loc_us-gaap_NoncontrollingInterestMember_53E0B8F347194DCCF620F985A86C6A69" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LSVAssetManagementMember" xlink:label="loc_seic_LSVAssetManagementMember_D609D81D321623810EB7F985A86C1CC7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09" xlink:to="loc_seic_LSVAssetManagementMember_D609D81D321623810EB7F985A86C1CC7" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_LsvEmployeeGroupMember" xlink:label="loc_seic_LsvEmployeeGroupMember_CE0D2752E4351E7113BFF985A86C1C3D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_7AC259ABDE5D83426F34F985A86C9F09" xlink:to="loc_seic_LsvEmployeeGroupMember_CE0D2752E4351E7113BFF985A86C1C3D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MovementInMinorityInterestRollForward" xlink:label="loc_us-gaap_MovementInMinorityInterestRollForward_6B0204E5F7C0D0A4D890F985A86C1DF0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_74FEECDB5795F8777382F985A86C231B" xlink:to="loc_us-gaap_MovementInMinorityInterestRollForward_6B0204E5F7C0D0A4D890F985A86C1DF0" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinorityInterest" xlink:label="loc_us-gaap_MinorityInterest_E514C68A727089F857D1F985A86C4795" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMinorityInterestRollForward_6B0204E5F7C0D0A4D890F985A86C1DF0" xlink:to="loc_us-gaap_MinorityInterest_E514C68A727089F857D1F985A86C4795" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_7A21C9FEC4732AF6B686F985A86CA3FB" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMinorityInterestRollForward_6B0204E5F7C0D0A4D890F985A86C1DF0" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_7A21C9FEC4732AF6B686F985A86CA3FB" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest_12B1756224F851745FF6F985A86C8A19" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMinorityInterestRollForward_6B0204E5F7C0D0A4D890F985A86C1DF0" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToNoncontrollingInterest_12B1756224F851745FF6F985A86C8A19" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation" xlink:label="loc_us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation_23B0CD62EC9D581932E8F985A86C6CBC" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInMinorityInterestRollForward_6B0204E5F7C0D0A4D890F985A86C1DF0" xlink:to="loc_us-gaap_NoncontrollingInterestDecreaseFromDeconsolidation_23B0CD62EC9D581932E8F985A86C6CBC" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/ShareholdersEquityStockOptionPlansDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9D8996B1A8BBDFC4BBC874A88E0525E0" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9D8996B1A8BBDFC4BBC874A88E0525E0" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_2FBD51213F4EDF4E21C574A88E05414C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_9D8996B1A8BBDFC4BBC874A88E0525E0" xlink:to="loc_us-gaap_AwardTypeAxis_2FBD51213F4EDF4E21C574A88E05414C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0623AF394FA29E6950974A88E05100C_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2FBD51213F4EDF4E21C574A88E05414C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0623AF394FA29E6950974A88E05100C_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0623AF394FA29E6950974A88E05100C" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2FBD51213F4EDF4E21C574A88E05414C" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0623AF394FA29E6950974A88E05100C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockOptionsMember" xlink:label="loc_us-gaap_StockOptionsMember_CEC78FDAE06B76DC781274A88E05645E" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_C0623AF394FA29E6950974A88E05100C" xlink:to="loc_us-gaap_StockOptionsMember_CEC78FDAE06B76DC781274A88E05645E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_74BD705E0EE64BD5687274A88E05D802" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_74BD705E0EE64BD5687274A88E05D802" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_8DD413830493C2731F5E74A88E05E048" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_8DD413830493C2731F5E74A88E05E048" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_16EAE70F543DEB9DB90574A88E05B44E" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod_16EAE70F543DEB9DB90574A88E05B44E" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_0CF2B5CB1AC3044BB01C74A88E05A078" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_0CF2B5CB1AC3044BB01C74A88E05A078" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_D6C595FDCF124804BAB474A88E054B85" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_D6C595FDCF124804BAB474A88E054B85" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_0035CD7B3C4197CD2C6674A88E060D46" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_0035CD7B3C4197CD2C6674A88E060D46" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_DF12A813BF04AE955AB374A88E060D03" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod_DF12A813BF04AE955AB374A88E060D03" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_98EA86EB0B978E9AD00674A88E068211" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExpirationsInPeriodWeightedAverageExercisePrice_98EA86EB0B978E9AD00674A88E068211" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_D0F2092E3C06EAA9E65774A88E06A5D8" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_D0F2092E3C06EAA9E65774A88E06A5D8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_D288CDF331853446F9CE74A88E06CFA1" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_D288CDF331853446F9CE74A88E06CFA1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_A90BAE30F7CB4C09197874A88E06F7CA" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_5EF746AB4AA9BB92B73674A88E0543D7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_A90BAE30F7CB4C09197874A88E06F7CA" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/ShareholdersEquityStockOptionsOutstandingAndExercisableDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_0146A0B75746746067F1F56B26AB10B3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_0146A0B75746746067F1F56B26AB10B3" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_0A08421BAFEAD5E83725F56B26ABA8B8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_0146A0B75746746067F1F56B26AB10B3" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_0A08421BAFEAD5E83725F56B26ABA8B8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_0A08421BAFEAD5E83725F56B26ABA8B8" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_0A08421BAFEAD5E83725F56B26ABA8B8" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_FirstRangeOfExercisePricesMember" xlink:label="loc_seic_FirstRangeOfExercisePricesMember_9BACAA32F5D8195C09B6F56B26AB4FC9" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:to="loc_seic_FirstRangeOfExercisePricesMember_9BACAA32F5D8195C09B6F56B26AB4FC9" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SecondRangeOfExercisePricesMember" xlink:label="loc_seic_SecondRangeOfExercisePricesMember_4E9C8ADC0C9E36631E3EF56B26AB2DAA" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:to="loc_seic_SecondRangeOfExercisePricesMember_4E9C8ADC0C9E36631E3EF56B26AB2DAA" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_ThirdRangeOfExercisePricesMember" xlink:label="loc_seic_ThirdRangeOfExercisePricesMember_5825D6E772F8A83B1748F56B26ABD0EB" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:to="loc_seic_ThirdRangeOfExercisePricesMember_5825D6E772F8A83B1748F56B26ABD0EB" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_FourthRangeOfExercisePricesMember" xlink:label="loc_seic_FourthRangeOfExercisePricesMember_04275CA70197D531FC2EF56B26ABC411" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:to="loc_seic_FourthRangeOfExercisePricesMember_04275CA70197D531FC2EF56B26ABC411" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_FifthRangeOfExercisePricesMember" xlink:label="loc_seic_FifthRangeOfExercisePricesMember_3A16BFA3FDBFC64B82FEF56B26AB2E4B" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_0B5F018BB4B62F36EC10F56B26AB69A8" xlink:to="loc_seic_FifthRangeOfExercisePricesMember_3A16BFA3FDBFC64B82FEF56B26AB2E4B" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_699F6C2BC05C432F8AAAF56B26AB4DED" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_699F6C2BC05C432F8AAAF56B26AB4DED" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_376AA89B9E04D8BBBD16F56B26ABBEB7" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_376AA89B9E04D8BBBD16F56B26ABBEB7" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_4D964CFB1B102783C3E0F56B26AB7860" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_4D964CFB1B102783C3E0F56B26AB7860" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_86121FA8744994BE7C07F56B26ABEC61" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_86121FA8744994BE7C07F56B26ABEC61" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_24002CFB1E7962ACA988F56B26ACD8FD" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_24002CFB1E7962ACA988F56B26ACD8FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_0E051E25CE5A352284B0F56B26AC50EC" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_0E051E25CE5A352284B0F56B26AC50EC" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_13CB7182CB0D935EB4E7F56B26ACB8F8" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_13CB7182CB0D935EB4E7F56B26ACB8F8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_A0883E6BBD7BEED1DB11F56B26ACAC38" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_6CC3826E7DA87BB195E0F56B26AB9EC9" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit_A0883E6BBD7BEED1DB11F56B26ACAC38" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/SummaryOfSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:type="locator" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SummaryOfSignificantAccountingPoliciesTable" xlink:label="loc_seic_SummaryOfSignificantAccountingPoliciesTable_151641F8500DB876BF0BF966B6D2EEE5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_seic_SummaryOfSignificantAccountingPoliciesTable_151641F8500DB876BF0BF966B6D2EEE5" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_CC5834BC2243131E26B5F966B6D217C5" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_seic_SummaryOfSignificantAccountingPoliciesTable_151641F8500DB876BF0BF966B6D2EEE5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_CC5834BC2243131E26B5F966B6D217C5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_CC5834BC2243131E26B5F966B6D217C5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_CC5834BC2243131E26B5F966B6D217C5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_C575416A8ED81DAB860BF966B6D2033A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_C575416A8ED81DAB860BF966B6D2033A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:label="loc_us-gaap_ComputerEquipmentMember_BF8119D708CDE82BBE63F966B6D2C828" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796" xlink:to="loc_us-gaap_ComputerEquipmentMember_BF8119D708CDE82BBE63F966B6D2C828" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_F6EC8CA824A29D78C1C9F966B6D28B21" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_08BC62169D37E8C1FE20F966B6D22796" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_F6EC8CA824A29D78C1C9F966B6D28B21" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_783F65078F331CDFC194F966B6D2DEB1" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_seic_SummaryOfSignificantAccountingPoliciesTable_151641F8500DB876BF0BF966B6D2EEE5" xlink:to="loc_dei_LegalEntityAxis_783F65078F331CDFC194F966B6D2DEB1" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_783F65078F331CDFC194F966B6D2DEB1" xlink:to="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2012/dei-2012-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_783F65078F331CDFC194F966B6D2DEB1" xlink:to="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_NoncontrollingInterestMember" xlink:label="loc_us-gaap_NoncontrollingInterestMember_A2D9A22AF5EBD32E661FF966B6D25570" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:to="loc_us-gaap_NoncontrollingInterestMember_A2D9A22AF5EBD32E661FF966B6D25570" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvesteeMember" xlink:label="loc_us-gaap_EquityMethodInvesteeMember_7913AEF0052B7C880C1AF966B6D2E0E3" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:to="loc_us-gaap_EquityMethodInvesteeMember_7913AEF0052B7C880C1AF966B6D2E0E3" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SeiSponsoredOpenEndedMoneyMarketMutualFundsMember" xlink:label="loc_seic_SeiSponsoredOpenEndedMoneyMarketMutualFundsMember_DE6FBD8EA15BD609B0D1F966B6D28CBA" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:to="loc_seic_SeiSponsoredOpenEndedMoneyMarketMutualFundsMember_DE6FBD8EA15BD609B0D1F966B6D28CBA" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SeiInvestmentsEuropeLimitedMember" xlink:label="loc_seic_SeiInvestmentsEuropeLimitedMember_8F9E5DBD037EEDD1344DF966B6D26C2F" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:to="loc_seic_SeiInvestmentsEuropeLimitedMember_8F9E5DBD037EEDD1344DF966B6D26C2F" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SeiInvestmentsDistributionCoSidcoMember" xlink:label="loc_seic_SeiInvestmentsDistributionCoSidcoMember_1688FE0F7775A6BF585AF966B6D20494" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_89A1D869381F1672BB37F966B6D2D8FD" xlink:to="loc_seic_SeiInvestmentsDistributionCoSidcoMember_1688FE0F7775A6BF585AF966B6D20494" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_CCB6FD43ED98DEE6A388F966B6D2D58D" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_seic_SummaryOfSignificantAccountingPoliciesTable_151641F8500DB876BF0BF966B6D2EEE5" xlink:to="loc_us-gaap_RangeAxis_CCB6FD43ED98DEE6A388F966B6D2D58D" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_B486E6B3943AD7330F05F966B6D21946_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RangeAxis_CCB6FD43ED98DEE6A388F966B6D2D58D" xlink:to="loc_us-gaap_RangeMember_B486E6B3943AD7330F05F966B6D21946_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_B486E6B3943AD7330F05F966B6D21946" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RangeAxis_CCB6FD43ED98DEE6A388F966B6D2D58D" xlink:to="loc_us-gaap_RangeMember_B486E6B3943AD7330F05F966B6D21946" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_2428D57BDA81DBA09AFFF966B6D22CB3" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_B486E6B3943AD7330F05F966B6D21946" xlink:to="loc_us-gaap_MinimumMember_2428D57BDA81DBA09AFFF966B6D22CB3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_CDF911627C71F0A81E40F966B6D27B63" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RangeMember_B486E6B3943AD7330F05F966B6D21946" xlink:to="loc_us-gaap_MaximumMember_CDF911627C71F0A81E40F966B6D27B63" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesAxis" xlink:label="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesAxis_22C593ABD9513090A3B5F966B6D245B8" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_seic_SummaryOfSignificantAccountingPoliciesTable_151641F8500DB876BF0BF966B6D2EEE5" xlink:to="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesAxis_22C593ABD9513090A3B5F966B6D245B8" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain" xlink:label="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain_797348D3D09A7DC4F9D2F966B6D28628_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesAxis_22C593ABD9513090A3B5F966B6D245B8" xlink:to="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain_797348D3D09A7DC4F9D2F966B6D28628_default" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain" xlink:label="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain_797348D3D09A7DC4F9D2F966B6D28628" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesAxis_22C593ABD9513090A3B5F966B6D245B8" xlink:to="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain_797348D3D09A7DC4F9D2F966B6D28628" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_GlobalWealthPlatformMember" xlink:label="loc_seic_GlobalWealthPlatformMember_EC586039A37D48E3628AF966B6D21D77" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_seic_CapitalizedSoftwareSummaryOfSignificantAccountingPoliciesDomain_797348D3D09A7DC4F9D2F966B6D28628" xlink:to="loc_seic_GlobalWealthPlatformMember_EC586039A37D48E3628AF966B6D21D77" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_98F6AE64364DF55EE8A8F966B6D25F26" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_98F6AE64364DF55EE8A8F966B6D25F26" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_156CFA9E50F137F9CDB5F966B6D25AC6" xlink:type="locator" />
    <link:definitionArc order="2" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_156CFA9E50F137F9CDB5F966B6D25AC6" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_73C6F50A198AE865BAA0F966B6D26B6A" xlink:type="locator" />
    <link:definitionArc order="3" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_73C6F50A198AE865BAA0F966B6D26B6A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalents" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_BA5150EF2C21EF249781F966B6D2ED4C" xlink:type="locator" />
    <link:definitionArc order="4" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_BA5150EF2C21EF249781F966B6D2ED4C" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_D4C2558369462E2CA3E3F966B6D2ACF2" xlink:type="locator" />
    <link:definitionArc order="5" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_D4C2558369462E2CA3E3F966B6D2ACF2" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalizedComputerSoftwareGross" xlink:label="loc_us-gaap_CapitalizedComputerSoftwareGross_B90AB203A46C3DF339EAF966B6D2B303" xlink:type="locator" />
    <link:definitionArc order="6" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_CapitalizedComputerSoftwareGross_B90AB203A46C3DF339EAF966B6D2B303" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalizedComputerSoftwareAccumulatedAmortization" xlink:label="loc_us-gaap_CapitalizedComputerSoftwareAccumulatedAmortization_5C9CEF36218FF880504FF966B6D2A6E3" xlink:type="locator" />
    <link:definitionArc order="7" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_CapitalizedComputerSoftwareAccumulatedAmortization_5C9CEF36218FF880504FF966B6D2A6E3" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CapitalizedSoftwareDevelopmentCostsInProgressAssociatedWithFutureReleasesSummaryOfSignificantAccountingPolicies" xlink:label="loc_seic_CapitalizedSoftwareDevelopmentCostsInProgressAssociatedWithFutureReleasesSummaryOfSignificantAccountingPolicies_24A60701EE44F630FC84F966B6E2D9D9" xlink:type="locator" />
    <link:definitionArc order="8" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_seic_CapitalizedSoftwareDevelopmentCostsInProgressAssociatedWithFutureReleasesSummaryOfSignificantAccountingPolicies_24A60701EE44F630FC84F966B6E2D9D9" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_PaymentsToAcquireSoftware" xlink:label="loc_us-gaap_PaymentsToAcquireSoftware_38342F13DCE7356D65B6F966B6E2D241" xlink:type="locator" />
    <link:definitionArc order="9" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_PaymentsToAcquireSoftware_38342F13DCE7356D65B6F966B6E2D241" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_SoftwareDevelopmentCostUsefulLife" xlink:label="loc_seic_SoftwareDevelopmentCostUsefulLife_89D142C0EBDDCBE85CA5F966B6E2A48C" xlink:type="locator" />
    <link:definitionArc order="10" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_seic_SoftwareDevelopmentCostUsefulLife_89D142C0EBDDCBE85CA5F966B6E2A48C" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_CapitalizedSoftwareWeightedAverageRemainingLife" xlink:label="loc_seic_CapitalizedSoftwareWeightedAverageRemainingLife_25656C9DB60C6800051DF966B6E2CE43" xlink:type="locator" />
    <link:definitionArc order="11" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_seic_CapitalizedSoftwareWeightedAverageRemainingLife_25656C9DB60C6800051DF966B6E2CE43" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalizedComputerSoftwareAmortization" xlink:label="loc_us-gaap_CapitalizedComputerSoftwareAmortization_E6A5994D2A946F6EC29FF966B6E2451F" xlink:type="locator" />
    <link:definitionArc order="12" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_CapitalizedComputerSoftwareAmortization_E6A5994D2A946F6EC29FF966B6E2451F" xlink:type="arc" />
    <link:loc xlink:href="seic-20121231.xsd#seic_AcceleratedAmortizationForGwpAbandonedComponents" xlink:label="loc_seic_AcceleratedAmortizationForGwpAbandonedComponents_610992FCB5A38D96C52AF966B6E25E4A" xlink:type="locator" />
    <link:definitionArc order="13" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_seic_AcceleratedAmortizationForGwpAbandonedComponents_610992FCB5A38D96C52AF966B6E25E4A" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_CapitalizedComputerSoftwareImpairments" xlink:label="loc_us-gaap_CapitalizedComputerSoftwareImpairments_D37D6E386E5A88792C23F966B6E249E8" xlink:type="locator" />
    <link:definitionArc order="14" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_CapitalizedComputerSoftwareImpairments_D37D6E386E5A88792C23F966B6E249E8" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ForeignCurrencyTransactionGainLossRealized" xlink:label="loc_us-gaap_ForeignCurrencyTransactionGainLossRealized_51B5AD295F3409FC61F1F966B6E2BFD3" xlink:type="locator" />
    <link:definitionArc order="15" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_ForeignCurrencyTransactionGainLossRealized_51B5AD295F3409FC61F1F966B6E2BFD3" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_A0F05C4ED4DADD851C75F966B6E206D5" xlink:type="locator" />
    <link:definitionArc order="16" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_A0F05C4ED4DADD851C75F966B6E206D5" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitAmount_1606C22936FF01852EFBF97112A4065B" xlink:type="locator" />
    <link:definitionArc order="17" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_3B39B36E1F18A7429243F966B6D24A1B" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfNetIncomePerOutstandingUnitAmount_1606C22936FF01852EFBF97112A4065B" xlink:type="arc" />
  </link:definitionLink>
  <link:definitionLink xlink:role="http://www.seic.com/role/VariableInterestEntitiesInvestmentProductsDetails" xlink:type="extended">
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_VariableInterestEntityLineItems" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_9BDB2F76E9B8B694DC292AC4384398B4" xlink:type="locator" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_4B58ECDC06FB8801215B2AC43843927A" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_9BDB2F76E9B8B694DC292AC4384398B4" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_4B58ECDC06FB8801215B2AC43843927A" xlink:type="arc" xbrldt:closed="true" xbrldt:contextElement="segment" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E014473AA0DE1E76A6892AC438433132" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_4B58ECDC06FB8801215B2AC43843927A" xlink:to="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E014473AA0DE1E76A6892AC438433132" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_B29368920E24125B8EE52AC438433478_default" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E014473AA0DE1E76A6892AC438433132" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_B29368920E24125B8EE52AC438433478_default" xlink:type="arc" />
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2012/elts/us-gaap-2012-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_B29368920E24125B8EE52AC438433478" xlink:type="locator" />
    <link:definitionArc order="1" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_E014473AA0DE1E76A6892AC438433132" xlink:to="loc_us-gaap_ClassificationOfVariableInterestEntityDomain_B29368920E24125B8EE52AC438433478" xlink:type="arc" />
  </link:definitionLink>
</link:linkbase>
