<?xml version="1.0" encoding="utf-8"?>
<Return xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" returnVersion="2022v5.0">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2024-05-14T13:07:20+00:00</ReturnTs>
    <TaxPeriodEndDt>2023-06-30</TaxPeriodEndDt>
    <ReturnTypeCd>990</ReturnTypeCd>
    <TaxPeriodBeginDt>2022-07-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>043177556</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>Massachusetts Institute of Technology Welfare Benefit Plans Trust</BusinessNameLine1Txt>
      </BusinessName>
      <BusinessNameControlTxt>MASS</BusinessNameControlTxt>
      <PhoneNum>6172532734</PhoneNum>
      <USAddress>
        <AddressLine1Txt>77 Massachusetts Avenue NE49-3142</AddressLine1Txt>
        <CityNm>Cambridge</CityNm>
        <StateAbbreviationCd>MA</StateAbbreviationCd>
        <ZIPCd>02139</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>JODI KESSLER</PersonNm>
      <PersonTitleTxt>DIRECTOR, TAX AND GLOBAL OPERATIONS</PersonTitleTxt>
      <PhoneNum>6173248969</PhoneNum>
      <SignatureDt>2024-05-14</SignatureDt>
    </BusinessOfficerGrp>
    <SigningOfficerGrp>
      <PersonFullName>
        <PersonFirstNm>JODI</PersonFirstNm>
        <PersonLastNm>KESSLER</PersonLastNm>
      </PersonFullName>
      <SSN>999009999</SSN>
    </SigningOfficerGrp>
    <TaxYr>2022</TaxYr>
    <BuildTS>2023-04-26 12:10:37Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="6">
    <IRS990 documentId="IRS990" softwareId="22016089" softwareVersionNum="2022v5.0">
      <PrincipalOfcrBusinessName>
        <BusinessNameLine1Txt>GLEN SHOR</BusinessNameLine1Txt>
      </PrincipalOfcrBusinessName>
      <USAddress>
        <AddressLine1Txt>77 Massachusetts Avenue</AddressLine1Txt>
        <CityNm>Cambridge</CityNm>
        <StateAbbreviationCd>MA</StateAbbreviationCd>
        <ZIPCd>02139</ZIPCd>
      </USAddress>
      <GrossReceiptsAmt>633242000</GrossReceiptsAmt>
      <GroupReturnForAffiliatesInd>false</GroupReturnForAffiliatesInd>
      <Organization501c3Ind>X</Organization501c3Ind>
      <WebsiteAddressTxt>N/A</WebsiteAddressTxt>
      <TypeOfOrganizationTrustInd>X</TypeOfOrganizationTrustInd>
      <FormationYr>1992</FormationYr>
      <LegalDomicileStateCd>MA</LegalDomicileStateCd>
      <ActivityOrMissionDesc>TO PROVIDE HEALTH AND LIFE INSURANCE BENEFITS TO COVERED ELIGIBLE RETIREES OF MASSACHUSETTS INSTITUTE OF TECHNOLOGY AND THEIR DEPENDENTS, AS WELL AS INDIVIDUALS RECEIVING LONG-TERM DISABILITY BENEFITS FOR AT LEAST THREE YEARS.</ActivityOrMissionDesc>
      <VotingMembersGoverningBodyCnt>2</VotingMembersGoverningBodyCnt>
      <VotingMembersIndependentCnt>0</VotingMembersIndependentCnt>
      <TotalEmployeeCnt>0</TotalEmployeeCnt>
      <TotalGrossUBIAmt>1701000</TotalGrossUBIAmt>
      <NetUnrelatedBusTxblIncmAmt>783507</NetUnrelatedBusTxblIncmAmt>
      <CYContributionsGrantsAmt>0</CYContributionsGrantsAmt>
      <PYProgramServiceRevenueAmt>20222000</PYProgramServiceRevenueAmt>
      <CYProgramServiceRevenueAmt>23286000</CYProgramServiceRevenueAmt>
      <PYInvestmentIncomeAmt>164460000</PYInvestmentIncomeAmt>
      <CYInvestmentIncomeAmt>52657000</CYInvestmentIncomeAmt>
      <CYOtherRevenueAmt>0</CYOtherRevenueAmt>
      <PYTotalRevenueAmt>184682000</PYTotalRevenueAmt>
      <CYTotalRevenueAmt>75943000</CYTotalRevenueAmt>
      <CYGrantsAndSimilarPaidAmt>0</CYGrantsAndSimilarPaidAmt>
      <PYBenefitsPaidToMembersAmt>39970000</PYBenefitsPaidToMembersAmt>
      <CYBenefitsPaidToMembersAmt>48479000</CYBenefitsPaidToMembersAmt>
      <CYSalariesCompEmpBnftPaidAmt>0</CYSalariesCompEmpBnftPaidAmt>
      <CYTotalProfFndrsngExpnsAmt>0</CYTotalProfFndrsngExpnsAmt>
      <CYTotalFundraisingExpenseAmt>0</CYTotalFundraisingExpenseAmt>
      <PYOtherExpensesAmt>2728000</PYOtherExpensesAmt>
      <CYOtherExpensesAmt>2505000</CYOtherExpensesAmt>
      <PYTotalExpensesAmt>42698000</PYTotalExpensesAmt>
      <CYTotalExpensesAmt>50984000</CYTotalExpensesAmt>
      <PYRevenuesLessExpensesAmt>141984000</PYRevenuesLessExpensesAmt>
      <CYRevenuesLessExpensesAmt>24959000</CYRevenuesLessExpensesAmt>
      <TotalAssetsBOYAmt>957104000</TotalAssetsBOYAmt>
      <TotalAssetsEOYAmt>937723000</TotalAssetsEOYAmt>
      <TotalLiabilitiesBOYAmt>4693000</TotalLiabilitiesBOYAmt>
      <TotalLiabilitiesEOYAmt>22974000</TotalLiabilitiesEOYAmt>
      <NetAssetsOrFundBalancesBOYAmt>952411000</NetAssetsOrFundBalancesBOYAmt>
      <NetAssetsOrFundBalancesEOYAmt>914749000</NetAssetsOrFundBalancesEOYAmt>
      <MissionDesc>TO PROVIDE HEALTH AND LIFE INSURANCE BENEFITS TO COVERED ELIGIBLE RETIREES OF MASSACHUSETTS INSTITUTE OF TECHNOLOGY AND THEIR DEPENDENTS, AS WELL AS INDIVIDUALS RECEIVING LONG-TERM DISABILITY BENEFITS FOR AT LEAST THREE YEARS.</MissionDesc>
      <SignificantNewProgramSrvcInd>false</SignificantNewProgramSrvcInd>
      <SignificantChangeInd>false</SignificantChangeInd>
      <ExpenseAmt>50367000</ExpenseAmt>
      <RevenueAmt>23286000</RevenueAmt>
      <Desc>MEDICAL AND LIFE INSURANCE BENEFITS FOR ELIGIBLE RETIREES, ALONG WITH MEDICAL BENEFITS FOR THOSE RECEIVING LONG TERM DISABILITY BENEFITS FOR AT LEAST THREE YEARS, WERE PROVIDED TO APPROXIMATELY 7237 INDIVIDUALS COVERED UNDER THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY (MIT) WELFARE BENEFIT PLANS TRUST.</Desc>
      <TotalProgramServiceExpensesAmt>50367000</TotalProgramServiceExpensesAmt>
      <DescribedInSection501c3Ind referenceDocumentId="IRS990ScheduleA">true</DescribedInSection501c3Ind>
      <ScheduleBRequiredInd>false</ScheduleBRequiredInd>
      <PoliticalCampaignActyInd>false</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>false</LobbyingActivitiesInd>
      <DonorAdvisedFundInd>false</DonorAdvisedFundInd>
      <ConservationEasementsInd>false</ConservationEasementsInd>
      <CollectionsOfArtInd>false</CollectionsOfArtInd>
      <CreditCounselingInd>false</CreditCounselingInd>
      <DonorRstrOrQuasiEndowmentsInd>false</DonorRstrOrQuasiEndowmentsInd>
      <ReportLandBuildingEquipmentInd>false</ReportLandBuildingEquipmentInd>
      <ReportInvestmentsOtherSecInd referenceDocumentId="IRS990ScheduleD">true</ReportInvestmentsOtherSecInd>
      <ReportProgramRelatedInvstInd>false</ReportProgramRelatedInvstInd>
      <ReportOtherAssetsInd>false</ReportOtherAssetsInd>
      <ReportOtherLiabilitiesInd referenceDocumentId="IRS990ScheduleD">true</ReportOtherLiabilitiesInd>
      <IncludeFIN48FootnoteInd referenceDocumentId="IRS990ScheduleD">true</IncludeFIN48FootnoteInd>
      <IndependentAuditFinclStmtInd referenceDocumentId="IRS990ScheduleD">true</IndependentAuditFinclStmtInd>
      <ConsolidatedAuditFinclStmtInd>false</ConsolidatedAuditFinclStmtInd>
      <SchoolOperatingInd>false</SchoolOperatingInd>
      <ForeignOfficeInd>false</ForeignOfficeInd>
      <ForeignActivitiesInd>false</ForeignActivitiesInd>
      <MoreThan5000KToOrgInd>false</MoreThan5000KToOrgInd>
      <MoreThan5000KToIndividualsInd>false</MoreThan5000KToIndividualsInd>
      <ProfessionalFundraisingInd>false</ProfessionalFundraisingInd>
      <FundraisingActivitiesInd>false</FundraisingActivitiesInd>
      <GamingActivitiesInd>false</GamingActivitiesInd>
      <OperateHospitalInd>false</OperateHospitalInd>
      <GrantsToOrganizationsInd>false</GrantsToOrganizationsInd>
      <GrantsToIndividualsInd>false</GrantsToIndividualsInd>
      <ScheduleJRequiredInd referenceDocumentId="IRS990ScheduleJ">true</ScheduleJRequiredInd>
      <TaxExemptBondsInd>false</TaxExemptBondsInd>
      <EngagedInExcessBenefitTransInd>false</EngagedInExcessBenefitTransInd>
      <PYExcessBenefitTransInd>false</PYExcessBenefitTransInd>
      <LoanOutstandingInd>false</LoanOutstandingInd>
      <GrantToRelatedPersonInd>false</GrantToRelatedPersonInd>
      <BusinessRlnWithOrgMemInd>false</BusinessRlnWithOrgMemInd>
      <BusinessRlnWithFamMemInd>false</BusinessRlnWithFamMemInd>
      <BusinessRlnWith35CtrlEntInd>false</BusinessRlnWith35CtrlEntInd>
      <DeductibleNonCashContriInd>false</DeductibleNonCashContriInd>
      <DeductibleArtContributionInd>false</DeductibleArtContributionInd>
      <TerminateOperationsInd>false</TerminateOperationsInd>
      <PartialLiquidationInd>false</PartialLiquidationInd>
      <DisregardedEntityInd>false</DisregardedEntityInd>
      <RelatedEntityInd referenceDocumentId="IRS990ScheduleR">true</RelatedEntityInd>
      <RelatedOrganizationCtrlEntInd>false</RelatedOrganizationCtrlEntInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>false</TrnsfrExmptNonChrtblRltdOrgInd>
      <ActivitiesConductedPrtshpInd>false</ActivitiesConductedPrtshpInd>
      <ScheduleORequiredInd>true</ScheduleORequiredInd>
      <IRPDocumentCnt>0</IRPDocumentCnt>
      <IRPDocumentW2GCnt>0</IRPDocumentW2GCnt>
      <EmployeeCnt>0</EmployeeCnt>
      <UnrelatedBusIncmOverLimitInd>true</UnrelatedBusIncmOverLimitInd>
      <Form990TFiledInd>true</Form990TFiledInd>
      <ForeignFinancialAccountInd>false</ForeignFinancialAccountInd>
      <ProhibitedTaxShelterTransInd>false</ProhibitedTaxShelterTransInd>
      <TaxablePartyNotificationInd>false</TaxablePartyNotificationInd>
      <NondeductibleContributionsInd>false</NondeductibleContributionsInd>
      <IndoorTanningServicesInd>false</IndoorTanningServicesInd>
      <SubjToTaxRmnrtnExPrchtPymtInd>false</SubjToTaxRmnrtnExPrchtPymtInd>
      <SubjectToExcsTaxNetInvstIncInd>false</SubjectToExcsTaxNetInvstIncInd>
      <InfoInScheduleOPartVIInd>X</InfoInScheduleOPartVIInd>
      <GoverningBodyVotingMembersCnt>2</GoverningBodyVotingMembersCnt>
      <IndependentVotingMemberCnt>0</IndependentVotingMemberCnt>
      <FamilyOrBusinessRlnInd>true</FamilyOrBusinessRlnInd>
      <DelegationOfMgmtDutiesInd>false</DelegationOfMgmtDutiesInd>
      <ChangeToOrgDocumentsInd>false</ChangeToOrgDocumentsInd>
      <MaterialDiversionOrMisuseInd>false</MaterialDiversionOrMisuseInd>
      <MembersOrStockholdersInd>false</MembersOrStockholdersInd>
      <ElectionOfBoardMembersInd>false</ElectionOfBoardMembersInd>
      <DecisionsSubjectToApprovaInd>false</DecisionsSubjectToApprovaInd>
      <MinutesOfGoverningBodyInd>true</MinutesOfGoverningBodyInd>
      <MinutesOfCommitteesInd>false</MinutesOfCommitteesInd>
      <OfficerMailingAddressInd>false</OfficerMailingAddressInd>
      <LocalChaptersInd>false</LocalChaptersInd>
      <Form990ProvidedToGvrnBodyInd>false</Form990ProvidedToGvrnBodyInd>
      <ConflictOfInterestPolicyInd>false</ConflictOfInterestPolicyInd>
      <WhistleblowerPolicyInd>false</WhistleblowerPolicyInd>
      <DocumentRetentionPolicyInd>false</DocumentRetentionPolicyInd>
      <CompensationProcessCEOInd>false</CompensationProcessCEOInd>
      <CompensationProcessOtherInd>false</CompensationProcessOtherInd>
      <InvestmentInJointVentureInd>true</InvestmentInJointVentureInd>
      <WrittenPolicyOrProcedureInd>true</WrittenPolicyOrProcedureInd>
      <StatesWhereCopyOfReturnIsFldCd>CA</StatesWhereCopyOfReturnIsFldCd>
      <UponRequestInd>X</UponRequestInd>
      <BooksInCareOfDetail>
        <BusinessName>
          <BusinessNameLine1Txt>JODI KESSLER</BusinessNameLine1Txt>
        </BusinessName>
        <PhoneNum>6173248969</PhoneNum>
        <USAddress>
          <AddressLine1Txt>77 Massachusetts Avenue NE49-3142</AddressLine1Txt>
          <CityNm>Cambridge</CityNm>
          <StateAbbreviationCd>MA</StateAbbreviationCd>
          <ZIPCd>02139</ZIPCd>
        </USAddress>
      </BooksInCareOfDetail>
      <Form990PartVIISectionAGrp>
        <BusinessName>
          <BusinessNameLine1Txt>Glen Shor</BusinessNameLine1Txt>
        </BusinessName>
        <TitleTxt>Trustee</TitleTxt>
        <AverageHoursPerWeekRt>1.0</AverageHoursPerWeekRt>
        <AverageHoursPerWeekRltdOrgRt>60.0</AverageHoursPerWeekRltdOrgRt>
        <IndividualTrusteeOrDirectorInd>X</IndividualTrusteeOrDirectorInd>
        <ReportableCompFromOrgAmt>0</ReportableCompFromOrgAmt>
        <ReportableCompFromRltdOrgAmt>795890</ReportableCompFromRltdOrgAmt>
        <OtherCompensationAmt>68243</OtherCompensationAmt>
      </Form990PartVIISectionAGrp>
      <Form990PartVIISectionAGrp>
        <BusinessName>
          <BusinessNameLine1Txt>Seth Alexander</BusinessNameLine1Txt>
        </BusinessName>
        <TitleTxt>Trustee</TitleTxt>
        <AverageHoursPerWeekRt>1.0</AverageHoursPerWeekRt>
        <AverageHoursPerWeekRltdOrgRt>60.0</AverageHoursPerWeekRltdOrgRt>
        <IndividualTrusteeOrDirectorInd>X</IndividualTrusteeOrDirectorInd>
        <ReportableCompFromOrgAmt>0</ReportableCompFromOrgAmt>
        <ReportableCompFromRltdOrgAmt>2635663</ReportableCompFromRltdOrgAmt>
        <OtherCompensationAmt>457443</OtherCompensationAmt>
      </Form990PartVIISectionAGrp>
      <TotalReportableCompFromOrgAmt>0</TotalReportableCompFromOrgAmt>
      <TotReportableCompRltdOrgAmt>3431553</TotReportableCompRltdOrgAmt>
      <TotalOtherCompensationAmt>525686</TotalOtherCompensationAmt>
      <IndivRcvdGreaterThan100KCnt>2</IndivRcvdGreaterThan100KCnt>
      <FormerOfcrEmployeesListedInd>false</FormerOfcrEmployeesListedInd>
      <TotalCompGreaterThan150KInd>true</TotalCompGreaterThan150KInd>
      <CompensationFromOtherSrcsInd>false</CompensationFromOtherSrcsInd>
      <ContractorCompensationGrp>
        <ContractorName>
          <BusinessName>
            <BusinessNameLine1Txt>WELLINGTON GROUP HOLDINGS LLP</BusinessNameLine1Txt>
          </BusinessName>
        </ContractorName>
        <ContractorAddress>
          <USAddress>
            <AddressLine1Txt>280 Congress St</AddressLine1Txt>
            <CityNm>Boston</CityNm>
            <StateAbbreviationCd>MA</StateAbbreviationCd>
            <ZIPCd>02210</ZIPCd>
          </USAddress>
        </ContractorAddress>
        <ServicesDesc>INVESTMENT MANAGER</ServicesDesc>
        <CompensationAmt>188592</CompensationAmt>
      </ContractorCompensationGrp>
      <ContractorCompensationGrp>
        <ContractorName>
          <BusinessName>
            <BusinessNameLine1Txt>STATE STREET BANK</BusinessNameLine1Txt>
          </BusinessName>
        </ContractorName>
        <ContractorAddress>
          <USAddress>
            <AddressLine1Txt>ONE LINCOLN STREET</AddressLine1Txt>
            <CityNm>BOSTON</CityNm>
            <StateAbbreviationCd>MA</StateAbbreviationCd>
            <ZIPCd>02210</ZIPCd>
          </USAddress>
        </ContractorAddress>
        <ServicesDesc>FINANCIAL CUSTODY SERVICES</ServicesDesc>
        <CompensationAmt>157559</CompensationAmt>
      </ContractorCompensationGrp>
      <CntrctRcvdGreaterThan100KCnt>2</CntrctRcvdGreaterThan100KCnt>
      <TotalContributionsAmt>0</TotalContributionsAmt>
      <ProgramServiceRevenueGrp>
        <Desc>Retiree Contributions</Desc>
        <BusinessCd>900099</BusinessCd>
        <TotalRevenueColumnAmt>11065000</TotalRevenueColumnAmt>
        <RelatedOrExemptFuncIncomeAmt>11065000</RelatedOrExemptFuncIncomeAmt>
      </ProgramServiceRevenueGrp>
      <ProgramServiceRevenueGrp>
        <Desc>Employer Group Waiver Plan</Desc>
        <BusinessCd>900099</BusinessCd>
        <TotalRevenueColumnAmt>12221000</TotalRevenueColumnAmt>
        <RelatedOrExemptFuncIncomeAmt>12221000</RelatedOrExemptFuncIncomeAmt>
      </ProgramServiceRevenueGrp>
      <TotalOthProgramServiceRevGrp>
        <TotalRevenueColumnAmt>0</TotalRevenueColumnAmt>
        <RelatedOrExemptFuncIncomeAmt>0</RelatedOrExemptFuncIncomeAmt>
        <UnrelatedBusinessRevenueAmt>0</UnrelatedBusinessRevenueAmt>
        <ExclusionAmt>0</ExclusionAmt>
      </TotalOthProgramServiceRevGrp>
      <TotalProgramServiceRevenueAmt>23286000</TotalProgramServiceRevenueAmt>
      <InvestmentIncomeGrp>
        <TotalRevenueColumnAmt>3886000</TotalRevenueColumnAmt>
        <UnrelatedBusinessRevenueAmt>1701000</UnrelatedBusinessRevenueAmt>
        <ExclusionAmt>2185000</ExclusionAmt>
      </InvestmentIncomeGrp>
      <RentalIncomeOrLossGrp>
        <RealAmt>0</RealAmt>
        <PersonalAmt>0</PersonalAmt>
      </RentalIncomeOrLossGrp>
      <GrossAmountSalesAssetsGrp>
        <SecuritiesAmt>606070000</SecuritiesAmt>
      </GrossAmountSalesAssetsGrp>
      <LessCostOthBasisSalesExpnssGrp>
        <SecuritiesAmt>557299000</SecuritiesAmt>
      </LessCostOthBasisSalesExpnssGrp>
      <GainOrLossGrp>
        <SecuritiesAmt>48771000</SecuritiesAmt>
        <OtherAmt>0</OtherAmt>
      </GainOrLossGrp>
      <NetGainOrLossInvestmentsGrp>
        <TotalRevenueColumnAmt>48771000</TotalRevenueColumnAmt>
        <ExclusionAmt>48771000</ExclusionAmt>
      </NetGainOrLossInvestmentsGrp>
      <MiscellaneousRevenueGrp>
        <TotalRevenueColumnAmt>0</TotalRevenueColumnAmt>
        <RelatedOrExemptFuncIncomeAmt>0</RelatedOrExemptFuncIncomeAmt>
        <UnrelatedBusinessRevenueAmt>0</UnrelatedBusinessRevenueAmt>
        <ExclusionAmt>0</ExclusionAmt>
      </MiscellaneousRevenueGrp>
      <OtherRevenueTotalAmt>0</OtherRevenueTotalAmt>
      <TotalRevenueGrp>
        <TotalRevenueColumnAmt>75943000</TotalRevenueColumnAmt>
        <RelatedOrExemptFuncIncomeAmt>23286000</RelatedOrExemptFuncIncomeAmt>
        <UnrelatedBusinessRevenueAmt>1701000</UnrelatedBusinessRevenueAmt>
        <ExclusionAmt>50956000</ExclusionAmt>
      </TotalRevenueGrp>
      <BenefitsToMembersGrp>
        <TotalAmt>48479000</TotalAmt>
        <ProgramServicesAmt>48479000</ProgramServicesAmt>
      </BenefitsToMembersGrp>
      <FeesForServicesOtherGrp>
        <TotalAmt>0</TotalAmt>
        <ProgramServicesAmt>0</ProgramServicesAmt>
        <ManagementAndGeneralAmt>0</ManagementAndGeneralAmt>
        <FundraisingAmt>0</FundraisingAmt>
      </FeesForServicesOtherGrp>
      <OtherExpensesGrp>
        <Desc>Claims Processing</Desc>
        <TotalAmt>1888000</TotalAmt>
        <ProgramServicesAmt>1888000</ProgramServicesAmt>
      </OtherExpensesGrp>
      <OtherExpensesGrp>
        <Desc>Administrative Expenses</Desc>
        <TotalAmt>617000</TotalAmt>
        <ManagementAndGeneralAmt>617000</ManagementAndGeneralAmt>
      </OtherExpensesGrp>
      <AllOtherExpensesGrp>
        <TotalAmt>0</TotalAmt>
        <ProgramServicesAmt>0</ProgramServicesAmt>
        <ManagementAndGeneralAmt>0</ManagementAndGeneralAmt>
        <FundraisingAmt>0</FundraisingAmt>
      </AllOtherExpensesGrp>
      <TotalFunctionalExpensesGrp>
        <TotalAmt>50984000</TotalAmt>
        <ProgramServicesAmt>50367000</ProgramServicesAmt>
        <ManagementAndGeneralAmt>617000</ManagementAndGeneralAmt>
        <FundraisingAmt>0</FundraisingAmt>
      </TotalFunctionalExpensesGrp>
      <CashNonInterestBearingGrp>
        <BOYAmt>18596000</BOYAmt>
        <EOYAmt>30704000</EOYAmt>
      </CashNonInterestBearingGrp>
      <ReceivablesFromOfficersEtcGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </ReceivablesFromOfficersEtcGrp>
      <RcvblFromDisqualifiedPrsnGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </RcvblFromDisqualifiedPrsnGrp>
      <LandBldgEquipCostOrOtherBssAmt>0</LandBldgEquipCostOrOtherBssAmt>
      <LandBldgEquipAccumDeprecAmt>0</LandBldgEquipAccumDeprecAmt>
      <LandBldgEquipBasisNetGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LandBldgEquipBasisNetGrp>
      <InvestmentsPubTradedSecGrp>
        <BOYAmt>226233000</BOYAmt>
        <EOYAmt>245835000</EOYAmt>
      </InvestmentsPubTradedSecGrp>
      <InvestmentsOtherSecuritiesGrp>
        <BOYAmt>704506000</BOYAmt>
        <EOYAmt>653404000</EOYAmt>
      </InvestmentsOtherSecuritiesGrp>
      <InvestmentsProgramRelatedGrp>
        <BOYAmt>0</BOYAmt>
      </InvestmentsProgramRelatedGrp>
      <OtherAssetsTotalGrp>
        <BOYAmt>7769000</BOYAmt>
        <EOYAmt>7780000</EOYAmt>
      </OtherAssetsTotalGrp>
      <TotalAssetsGrp>
        <BOYAmt>957104000</BOYAmt>
        <EOYAmt>937723000</EOYAmt>
      </TotalAssetsGrp>
      <AccountsPayableAccrExpnssGrp>
        <BOYAmt>1597000</BOYAmt>
        <EOYAmt>4836000</EOYAmt>
      </AccountsPayableAccrExpnssGrp>
      <LoansFromOfficersDirectorsGrp>
        <BOYAmt>0</BOYAmt>
        <EOYAmt>0</EOYAmt>
      </LoansFromOfficersDirectorsGrp>
      <OtherLiabilitiesGrp>
        <BOYAmt>3096000</BOYAmt>
        <EOYAmt>18138000</EOYAmt>
      </OtherLiabilitiesGrp>
      <TotalLiabilitiesGrp>
        <BOYAmt>4693000</BOYAmt>
        <EOYAmt>22974000</EOYAmt>
      </TotalLiabilitiesGrp>
      <NoDonorRestrictionNetAssetsGrp>
        <BOYAmt>952411000</BOYAmt>
        <EOYAmt>914749000</EOYAmt>
      </NoDonorRestrictionNetAssetsGrp>
      <TotalNetAssetsFundBalanceGrp>
        <BOYAmt>952411000</BOYAmt>
        <EOYAmt>914749000</EOYAmt>
      </TotalNetAssetsFundBalanceGrp>
      <TotLiabNetAssetsFundBalanceGrp>
        <BOYAmt>957104000</BOYAmt>
        <EOYAmt>937723000</EOYAmt>
      </TotLiabNetAssetsFundBalanceGrp>
      <ReconcilationRevenueExpnssAmt>24959000</ReconcilationRevenueExpnssAmt>
      <NetUnrlzdGainsLossesInvstAmt>-62621000</NetUnrlzdGainsLossesInvstAmt>
      <OtherChangesInNetAssetsAmt>0</OtherChangesInNetAssetsAmt>
      <MethodOfAccountingAccrualInd>X</MethodOfAccountingAccrualInd>
      <AccountantCompileOrReviewInd>false</AccountantCompileOrReviewInd>
      <FSAuditedInd>true</FSAuditedInd>
      <FSAuditedBasisGrp>
        <SeparateBasisFinclStmtInd>X</SeparateBasisFinclStmtInd>
      </FSAuditedBasisGrp>
      <AuditCommitteeInd>true</AuditCommitteeInd>
    </IRS990>
    <IRS990ScheduleA documentId="IRS990ScheduleA" softwareId="22016089" softwareVersionNum="2022v5.0">
      <SupportingOrganization509a3Ind>X</SupportingOrganization509a3Ind>
      <SupportingOrgType1Ind>X</SupportingOrgType1Ind>
      <IRSWrittenDeterminationInd>X</IRSWrittenDeterminationInd>
      <SupportedOrganizationsCnt>1</SupportedOrganizationsCnt>
      <SupportedOrgInformationGrp>
        <SupportedOrganizationName>
          <BusinessNameLine1Txt>MASSACHUSETTS INSTITUTE OF TECHNOLOGY</BusinessNameLine1Txt>
        </SupportedOrganizationName>
        <EIN>042103594</EIN>
        <OrganizationTypeCd>2</OrganizationTypeCd>
        <GoverningDocumentListedInd>true</GoverningDocumentListedInd>
        <SupportAmt>0</SupportAmt>
        <OtherSupportAmt>0</OtherSupportAmt>
      </SupportedOrgInformationGrp>
      <SupportedOrganizationsTotalCnt>1</SupportedOrganizationsTotalCnt>
      <SupportSumAmt>0</SupportSumAmt>
      <OtherSupportSumAmt>0</OtherSupportSumAmt>
      <Form990SchASupportingOrgGrp>
        <ListedByNameGoverningDocInd>true</ListedByNameGoverningDocInd>
        <SuprtOrgNoIRSDeterminationInd>false</SuprtOrgNoIRSDeterminationInd>
        <SupportedOrgSectionC456Ind>false</SupportedOrgSectionC456Ind>
        <SupportedOrgNotOrganizedUSInd>false</SupportedOrgNotOrganizedUSInd>
        <OrganizationChangeSuprtOrgInd>false</OrganizationChangeSuprtOrgInd>
        <SupportNonSupportedOrgInd>false</SupportNonSupportedOrgInd>
        <PaymentSubstantialContribtrInd>false</PaymentSubstantialContribtrInd>
        <LoanDisqualifiedPersonInd>false</LoanDisqualifiedPersonInd>
        <ControlledDisqualifiedPrsnInd>false</ControlledDisqualifiedPrsnInd>
        <DisqualifiedPrsnControllIntInd>false</DisqualifiedPrsnControllIntInd>
        <DisqualifiedPrsnOwnrIntInd>false</DisqualifiedPrsnOwnrIntInd>
        <ExcessBusinessHoldingsRulesInd>false</ExcessBusinessHoldingsRulesInd>
        <ContributionControllerInd>false</ContributionControllerInd>
        <ContributionFamilyInd>false</ContributionFamilyInd>
        <Contribution35ControlledInd>false</Contribution35ControlledInd>
      </Form990SchASupportingOrgGrp>
      <Form990SchAType1SuprtOrgGrp>
        <PowerAppointMajorityDirTrstInd>true</PowerAppointMajorityDirTrstInd>
        <OperateBenefitNonSuprtOrgInd>false</OperateBenefitNonSuprtOrgInd>
      </Form990SchAType1SuprtOrgGrp>
    </IRS990ScheduleA>
    <IRS990ScheduleD documentId="IRS990ScheduleD" softwareId="22016089" softwareVersionNum="2022v5.0">
      <FinancialDerivativesGrp>
        <BookValueAmt>283000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </FinancialDerivativesGrp>
      <CloselyHeldEquityInterestsGrp>
        <BookValueAmt>2390000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </CloselyHeldEquityInterestsGrp>
      <OtherSecuritiesGrp>
        <Desc>Partnership Investments</Desc>
        <BookValueAmt>648151000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </OtherSecuritiesGrp>
      <OtherSecuritiesGrp>
        <Desc>U.S. Government Agency</Desc>
        <BookValueAmt>1587000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </OtherSecuritiesGrp>
      <OtherSecuritiesGrp>
        <Desc>Repo</Desc>
        <BookValueAmt>700000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </OtherSecuritiesGrp>
      <OtherSecuritiesGrp>
        <Desc>Preferred Stock</Desc>
        <BookValueAmt>278000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </OtherSecuritiesGrp>
      <OtherSecuritiesGrp>
        <Desc>Domestic bonds</Desc>
        <BookValueAmt>15000</BookValueAmt>
        <MethodValuationCd>F</MethodValuationCd>
      </OtherSecuritiesGrp>
      <TotalBookValueSecuritiesAmt>653404000</TotalBookValueSecuritiesAmt>
      <OtherLiabilitiesOrgGrp>
        <Desc>Investments sold but not yet purchased</Desc>
        <Amt>18138000</Amt>
      </OtherLiabilitiesOrgGrp>
      <TotalLiabilityAmt>18138000</TotalLiabilityAmt>
      <FootnoteTextInd>X</FootnoteTextInd>
      <TotalRevEtcAuditedFinclStmtAmt>13322000</TotalRevEtcAuditedFinclStmtAmt>
      <NetUnrealizedGainsInvstAmt>-62621000</NetUnrealizedGainsInvstAmt>
      <OtherRevenueAmt>0</OtherRevenueAmt>
      <RevenueNotReportedAmt>-62621000</RevenueNotReportedAmt>
      <RevenueSubtotalAmt>75943000</RevenueSubtotalAmt>
      <OtherRevenuesNotIncludedAmt>0</OtherRevenuesNotIncludedAmt>
      <RevenueNotReportedFinclStmtAmt>0</RevenueNotReportedFinclStmtAmt>
      <TotalRevenuePerForm990Amt>75943000</TotalRevenuePerForm990Amt>
      <TotExpnsEtcAuditedFinclStmtAmt>50984000</TotExpnsEtcAuditedFinclStmtAmt>
      <OtherExpensesIncludedAmt>0</OtherExpensesIncludedAmt>
      <ExpensesNotReportedAmt>0</ExpensesNotReportedAmt>
      <ExpensesSubtotalAmt>50984000</ExpensesSubtotalAmt>
      <OtherExpensesNotIncludedAmt>0</OtherExpensesNotIncludedAmt>
      <ExpensesNotRptFinclStmtAmt>0</ExpensesNotRptFinclStmtAmt>
      <TotalExpensesPerForm990Amt>50984000</TotalExpensesPerForm990Amt>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Schedule D, Part X, Line 2 FIN 48 (ASC 740) footnote</FormAndLineReferenceDesc>
        <ExplanationTxt>U.S. GAAP requires an evaluation of tax positions taken and recognition of a tax liability (or asset) if the organization has taken an uncertain position that more likely than not would not be sustained upon examination by the Internal Revenue Service. The MIT Welfare Benefit Plans Trust has analyzed the tax positions taken and has concluded that as of June 30, 2023, there are no significant uncertain positions taken or expected to be taken.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleD>
    <IRS990ScheduleJ documentId="IRS990ScheduleJ" softwareId="22016089" softwareVersionNum="2022v5.0">
      <SeverancePaymentInd>false</SeverancePaymentInd>
      <SupplementalNonqualRtrPlanInd>true</SupplementalNonqualRtrPlanInd>
      <EquityBasedCompArrngmInd>false</EquityBasedCompArrngmInd>
      <CompBasedOnRevenueOfFlngOrgInd>false</CompBasedOnRevenueOfFlngOrgInd>
      <CompBsdOnRevRelatedOrgsInd>false</CompBsdOnRevRelatedOrgsInd>
      <CompBsdNetEarnsFlngOrgInd>false</CompBsdNetEarnsFlngOrgInd>
      <CompBsdNetEarnsRltdOrgsInd>false</CompBsdNetEarnsRltdOrgsInd>
      <AnyNonFixedPaymentsInd>false</AnyNonFixedPaymentsInd>
      <InitialContractExceptionInd>false</InitialContractExceptionInd>
      <RltdOrgOfficerTrstKeyEmplGrp>
        <BusinessName>
          <BusinessNameLine1Txt>Seth Alexander</BusinessNameLine1Txt>
        </BusinessName>
        <TitleTxt>Trustee</TitleTxt>
        <BaseCompensationFilingOrgAmt>0</BaseCompensationFilingOrgAmt>
        <CompensationBasedOnRltdOrgsAmt>911111</CompensationBasedOnRltdOrgsAmt>
        <BonusFilingOrganizationAmount>0</BonusFilingOrganizationAmount>
        <BonusRelatedOrganizationsAmt>1666438</BonusRelatedOrganizationsAmt>
        <OtherCompensationFilingOrgAmt>0</OtherCompensationFilingOrgAmt>
        <OtherCompensationRltdOrgsAmt>58114</OtherCompensationRltdOrgsAmt>
        <DeferredCompensationFlngOrgAmt>0</DeferredCompensationFlngOrgAmt>
        <DeferredCompRltdOrgsAmt>425126</DeferredCompRltdOrgsAmt>
        <NontaxableBenefitsFilingOrgAmt>0</NontaxableBenefitsFilingOrgAmt>
        <NontaxableBenefitsRltdOrgsAmt>32317</NontaxableBenefitsRltdOrgsAmt>
        <TotalCompensationFilingOrgAmt>0</TotalCompensationFilingOrgAmt>
        <TotalCompensationRltdOrgsAmt>3093106</TotalCompensationRltdOrgsAmt>
        <CompReportPrior990FilingOrgAmt>0</CompReportPrior990FilingOrgAmt>
        <CompReportPrior990RltdOrgsAmt>347857</CompReportPrior990RltdOrgsAmt>
      </RltdOrgOfficerTrstKeyEmplGrp>
      <RltdOrgOfficerTrstKeyEmplGrp>
        <BusinessName>
          <BusinessNameLine1Txt>Glen Shor</BusinessNameLine1Txt>
        </BusinessName>
        <TitleTxt>Trustee</TitleTxt>
        <BaseCompensationFilingOrgAmt>0</BaseCompensationFilingOrgAmt>
        <CompensationBasedOnRltdOrgsAmt>756890</CompensationBasedOnRltdOrgsAmt>
        <BonusFilingOrganizationAmount>0</BonusFilingOrganizationAmount>
        <BonusRelatedOrganizationsAmt>0</BonusRelatedOrganizationsAmt>
        <OtherCompensationFilingOrgAmt>0</OtherCompensationFilingOrgAmt>
        <OtherCompensationRltdOrgsAmt>39000</OtherCompensationRltdOrgsAmt>
        <DeferredCompensationFlngOrgAmt>0</DeferredCompensationFlngOrgAmt>
        <DeferredCompRltdOrgsAmt>36085</DeferredCompRltdOrgsAmt>
        <NontaxableBenefitsFilingOrgAmt>0</NontaxableBenefitsFilingOrgAmt>
        <NontaxableBenefitsRltdOrgsAmt>32158</NontaxableBenefitsRltdOrgsAmt>
        <TotalCompensationFilingOrgAmt>0</TotalCompensationFilingOrgAmt>
        <TotalCompensationRltdOrgsAmt>864133</TotalCompensationRltdOrgsAmt>
        <CompReportPrior990FilingOrgAmt>0</CompReportPrior990FilingOrgAmt>
        <CompReportPrior990RltdOrgsAmt>0</CompReportPrior990RltdOrgsAmt>
      </RltdOrgOfficerTrstKeyEmplGrp>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Schedule J, Part I, Line 4b Supplemental nonqualified retirement plan</FormAndLineReferenceDesc>
        <ExplanationTxt>An employee of the MIT Investment Management Company is eligible for incentive compensation based on the performance of the Institute's investments. A portion of their incentive compensation is paid in an initial calendar year, and the remainder is deferred to being paid in the subsequent calendar year contingent on continued service to MITIMCo through specified dates. Incentive compensation actually paid in calendar year 2022 is reflected in Column B(ii). This includes incentive compensation from prior calendar years for which payment was deferred, contingent on continued service. That amount is listed in Column F. Calendar year 2022 incentive compensation for which payment has been deferred contingent on continued service is included in Column C.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleJ>
    <IRS990ScheduleO documentId="IRS990ScheduleO" softwareId="22016089" softwareVersionNum="2022v5.0">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Line 2 Business Relationship</FormAndLineReferenceDesc>
        <ExplanationTxt>For fiscal year 2023, the following current trustee of the MIT Welfare Benefit Plans Trust was employed by the Massachusetts Institute of Technology, of which Glen Shor was also an officer and director: Seth Alexander.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Line 8b Documentation of meetings held by committees of governing body</FormAndLineReferenceDesc>
        <ExplanationTxt>THERE ARE NO SUCH COMMITTEES WITH AUTHORITY TO ACT ON BEHALF OF THE GOVERNING BODY.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Line 11b Review of form 990 by governing body</FormAndLineReferenceDesc>
        <ExplanationTxt>MIT WELFARE BENEFIT PLANS TRUST'S FORM 990 IS REVIEWED FOR ACCURACY AND COMPLETENESS PRIOR TO FILING UNDER THE DIRECTION OF THE TRUSTEES.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Line 19 Required documents available to the public</FormAndLineReferenceDesc>
        <ExplanationTxt>The organization's governing documents and financial statements are available upon request. The Massachusetts Institute of Technology (MIT)'s policies are available on MIT's website.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Lines 12-14 Policies and Procedures</FormAndLineReferenceDesc>
        <ExplanationTxt>BARRING SPECIFIC ACTION TO THE CONTRARY, MIT WELFARE BENEFIT PLANS TRUST FOLLOWS APPLICABLE WRITTEN POLICIES AND PROCEDURES OF MASSACHUSETTS INSTITUTE OF TECHNOLOGY.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
    <IRS990ScheduleR documentId="IRS990ScheduleR" softwareId="22016089" softwareVersionNum="2022v5.0">
      <IdRelatedTaxExemptOrgGrp>
        <DisregardedEntityName>
          <BusinessNameLine1Txt>MASSACHUSETTS INSTITUTE OF TECHNOLOGY</BusinessNameLine1Txt>
        </DisregardedEntityName>
        <USAddress>
          <AddressLine1Txt>77 MASSACHUSETTS AVENUE</AddressLine1Txt>
          <CityNm>CAMBRIDGE</CityNm>
          <StateAbbreviationCd>MA</StateAbbreviationCd>
          <ZIPCd>02139</ZIPCd>
        </USAddress>
        <EIN>042103594</EIN>
        <PrimaryActivitiesTxt>EDUCATION</PrimaryActivitiesTxt>
        <LegalDomicileStateCd>MA</LegalDomicileStateCd>
        <ExemptCodeSectionTxt>501(c)(3)</ExemptCodeSectionTxt>
        <PublicCharityStatusTxt>2</PublicCharityStatusTxt>
        <DirectControllingEntityName>
          <BusinessNameLine1Txt>NA</BusinessNameLine1Txt>
        </DirectControllingEntityName>
        <ControlledOrganizationInd>false</ControlledOrganizationInd>
      </IdRelatedTaxExemptOrgGrp>
      <ReceiptOfIntAnntsRntsRyltsInd>false</ReceiptOfIntAnntsRntsRyltsInd>
      <GiftGrntOrCapContriToOthOrgInd>false</GiftGrntOrCapContriToOthOrgInd>
      <GiftGrntCapContriFromOthOrgInd>false</GiftGrntCapContriFromOthOrgInd>
      <LoansOrGuaranteesToOtherOrgInd>false</LoansOrGuaranteesToOtherOrgInd>
      <LoansOrGuaranteesFromOthOrgInd>false</LoansOrGuaranteesFromOthOrgInd>
      <DivRelatedOrganizationInd>false</DivRelatedOrganizationInd>
      <AssetSaleToOtherOrgInd>false</AssetSaleToOtherOrgInd>
      <AssetPurchaseFromOtherOrgInd>false</AssetPurchaseFromOtherOrgInd>
      <AssetExchangeInd>false</AssetExchangeInd>
      <RentalOfFacilitiesToOthOrgInd>false</RentalOfFacilitiesToOthOrgInd>
      <RentalOfFcltsFromOthOrgInd>false</RentalOfFcltsFromOthOrgInd>
      <PerformOfServicesForOthOrgInd>false</PerformOfServicesForOthOrgInd>
      <PerformOfServicesByOtherOrgInd>false</PerformOfServicesByOtherOrgInd>
      <SharingOfFacilitiesInd>false</SharingOfFacilitiesInd>
      <PaidEmployeesSharingInd>false</PaidEmployeesSharingInd>
      <ReimbursementPaidToOtherOrgInd>false</ReimbursementPaidToOtherOrgInd>
      <ReimbursementPaidByOtherOrgInd>false</ReimbursementPaidByOtherOrgInd>
      <TransferToOtherOrgInd>false</TransferToOtherOrgInd>
      <TransferFromOtherOrgInd>false</TransferFromOtherOrgInd>
    </IRS990ScheduleR>
  </ReturnData>
</Return>
