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        <ExplanationTxt>THE TRUSTEE CANNOT BE REACHED AT THE ORGANIZATION'S MAILING ADDRESS. THEIR MAILING ADDRESS IS: TIAA TRUST N.A. 211 NORTH BROADWAY, SUITE 1000 ST LOUIS, MO 63102</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Line 11b Review of form 990 by governing body</FormAndLineReferenceDesc>
        <ExplanationTxt>THE TAX DEPARTMENT OF HHMI, THE PLAN SPONSOR, PREPARES A DRAFT FORM 990 BASED ON DATA REPORTED IN THE FINANCIAL STATEMENTS. THE DRAFT RETURN IS REVIEWED BY THE VEBA'S OUTSIDE TAX PREPARER. THE COMPLETED FORM 990 IS PROVIDED TO THE TRUSTEE FOR REVIEW PRIOR TO THE FILING DUE DATE. THE DATA IS REVIEWED AGAINST SOURCE DOCUMENTS FOR ACCURACY BEFORE THE FORM 990 IS SIGNED AND SUBMITTED TO THE IRS.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VI, Line 19 Required documents available to the public</FormAndLineReferenceDesc>
        <ExplanationTxt>GOVERNING DOCUMENTS, FINANCIAL STATEMENTS AND THE FORM 990 ARE AVAILABLE UPON REQUEST.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VII, Section A, Line 1a COMPENSATION INFORMATION</FormAndLineReferenceDesc>
        <ExplanationTxt>TIAA TRUST, N.A. RECEIVED ADDITIONAL INDIRECT COMPENSATION FOR ITS SERVICES AS TRUSTEE. TIAA TRUST, N.A. HAS PROVIDED ALL THE REQUIRED DISCLOSURES PURSUANT TO ERISA SECTION 408(B)(2).</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990, Part VII, Section A, Line 1a, Column (B) AVERAGE HOURS PER WEEK DEVOTED TO ORGANIZATION</FormAndLineReferenceDesc>
        <ExplanationTxt>AS TRUSTEE, TIAA TRUST, N.A. HAS PROVIDED VARIOUS ADMINISTRATIVE SERVICES TO THE TRUST, SUCH AS ADMINISTERING THIS BENEFIT PLAN. THESE SERVICES REQUIRE THE INVOLVEMENT OF NUMEROUS INDIVIDUAL EMPLOYEES IN THE ACTIVITIES OF THE ORGANIZATION AND THUS CAN NOT BE QUANTIFIED ON AN HOURLY BASIS, BUT INSTEAD ARE IN ACCORDANCE WITH THE TRUST AGREEMENTS WITH HOWARD HUGHES MEDICAL INSTITUTE.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>FORM 990, PART VI, SECTION B, LINES 12-15 GOVERNANCE AND POLICIES</FormAndLineReferenceDesc>
        <ExplanationTxt>THE TRUST IS A VOLUNTARY EMPLOYEE BENEFITS ASSOCIATION PURSUANT TO IRC SECTION 501(C)(9). ITS TRUSTEE HAS A FIDUCIARY DUTY TO MANAGE INVESTMENTS IN THE BEST INTEREST OF THE BENEFICIARIES AND OPERATE PURSUANT TO A STRINGENT CODE OF CONDUCT. SINCE THE TRUST DOES NOT MAINTAIN EMPLOYEES, THERE ARE NO PROCESSES IN PLACE RELATED TO EMPLOYEE COMPENSATION.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
    <IRS990ScheduleR documentId="IRS990ScheduleR" softwareId="23017437" softwareVersionNum="2023v5.1">
      <IdRelatedTaxExemptOrgGrp>
        <DisregardedEntityName>
          <BusinessNameLine1Txt>HOWARD HUGHES MEDICAL INSTITUTE</BusinessNameLine1Txt>
        </DisregardedEntityName>
        <USAddress>
          <AddressLine1Txt>4000 JONES BRIDGE ROAD</AddressLine1Txt>
          <CityNm>CHEVY CHASE</CityNm>
          <StateAbbreviationCd>MD</StateAbbreviationCd>
          <ZIPCd>208156789</ZIPCd>
        </USAddress>
        <EIN>590735717</EIN>
        <DirectControllingNACd>N/A</DirectControllingNACd>
      </IdRelatedTaxExemptOrgGrp>
      <ReceiptOfIntAnntsRntsRyltsInd>false</ReceiptOfIntAnntsRntsRyltsInd>
      <GiftGrntOrCapContriToOthOrgInd>false</GiftGrntOrCapContriToOthOrgInd>
      <GiftGrntCapContriFromOthOrgInd>true</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>true</SharingOfFacilitiesInd>
      <PaidEmployeesSharingInd>true</PaidEmployeesSharingInd>
      <ReimbursementPaidToOtherOrgInd>false</ReimbursementPaidToOtherOrgInd>
      <ReimbursementPaidByOtherOrgInd>true</ReimbursementPaidByOtherOrgInd>
      <TransferToOtherOrgInd>false</TransferToOtherOrgInd>
      <TransferFromOtherOrgInd>true</TransferFromOtherOrgInd>
    </IRS990ScheduleR>
  </ReturnData>
</Return>