﻿<?xml version="1.0" encoding="utf-8"?>
<Return xmlns="http://www.irs.gov/efile" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" returnVersion="2025v4.1" xsi:schemaLocation="http://www.irs.gov/efile">
  <ReturnHeader binaryAttachmentCnt="0">
    <ReturnTs>2026-08-23T07:23:41-07:00</ReturnTs>
    <TaxPeriodEndDt>2026-06-30</TaxPeriodEndDt>
    <PreparerFirmGrp>
      <PreparerFirmEIN>202203783</PreparerFirmEIN>
      <PreparerFirmName>
        <BusinessNameLine1Txt>ELLIOTT H PURETZ</BusinessNameLine1Txt>
      </PreparerFirmName>
      <PreparerUSAddress>
        <AddressLine1Txt>1501 BEACON STREET APT 1405</AddressLine1Txt>
        <CityNm>BROOKLINE</CityNm>
        <StateAbbreviationCd>MA</StateAbbreviationCd>
        <ZIPCd>02446</ZIPCd>
      </PreparerUSAddress>
    </PreparerFirmGrp>
    <ReturnTypeCd>990EZ</ReturnTypeCd>
    <TaxPeriodBeginDt>2025-07-01</TaxPeriodBeginDt>
    <Filer>
      <EIN>043489718</EIN>
      <BusinessName>
        <BusinessNameLine1Txt>CAMBRIDGE FORUM INC</BusinessNameLine1Txt>
      </BusinessName>
      <BusinessNameControlTxt>CAMB</BusinessNameControlTxt>
      <PhoneNum>6174952727</PhoneNum>
      <USAddress>
        <AddressLine1Txt>3 CHURCH STREET</AddressLine1Txt>
        <CityNm>CAMBRIDGE</CityNm>
        <StateAbbreviationCd>MA</StateAbbreviationCd>
        <ZIPCd>021383715</ZIPCd>
      </USAddress>
    </Filer>
    <BusinessOfficerGrp>
      <PersonNm>WENDY GRAHAM-COCO</PersonNm>
      <PersonTitleTxt>TREASURER</PersonTitleTxt>
      <PhoneNum>6174952727</PhoneNum>
      <SignatureDt>2026-08-17</SignatureDt>
    </BusinessOfficerGrp>
    <PreparerPersonGrp>
      <PreparerPersonNm>Elliott H Puretz CPA</PreparerPersonNm>
      <PTIN>P00161763</PTIN>
      <PhoneNum>6174603429</PhoneNum>
      <SelfEmployedInd>X</SelfEmployedInd>
    </PreparerPersonGrp>
    <TaxYr>2025</TaxYr>
    <BuildTS>2025-03-06 01:10:19Z</BuildTS>
  </ReturnHeader>
  <ReturnData documentCnt="4">
    <IRS990EZ documentId="IRS990EZ-01" referenceDocumentId="IRS990ScheduleO-01">
      <MethodOfAccountingAccrualInd>X</MethodOfAccountingAccrualInd>
      <WebsiteAddressTxt>www.cambridgeforum.org</WebsiteAddressTxt>
      <Organization501c3Ind referenceDocumentId="IRS990ScheduleA-01" referenceDocumentName="IRS990ScheduleA">X</Organization501c3Ind>
      <TypeOfOrganizationCorpInd>X</TypeOfOrganizationCorpInd>
      <GrossReceiptsAmt>121352</GrossReceiptsAmt>
      <InfoInScheduleOPartIInd>X</InfoInScheduleOPartIInd>
      <ContributionsGiftsGrantsEtcAmt>121352</ContributionsGiftsGrantsEtcAmt>
      <ProgramServiceRevenueAmt>0</ProgramServiceRevenueAmt>
      <MembershipDuesAmt>0</MembershipDuesAmt>
      <InvestmentIncomeAmt>0</InvestmentIncomeAmt>
      <CostOrOtherBasisExpenseSaleAmt>0</CostOrOtherBasisExpenseSaleAmt>
      <GainOrLossFromSaleOfAssetsAmt>0</GainOrLossFromSaleOfAssetsAmt>
      <FundraisingGrossIncomeAmt>0</FundraisingGrossIncomeAmt>
      <SpecialEventsDirectExpensesAmt>0</SpecialEventsDirectExpensesAmt>
      <SpecialEventsNetIncomeLossAmt>0</SpecialEventsNetIncomeLossAmt>
      <CostOfGoodsSoldAmt>0</CostOfGoodsSoldAmt>
      <GrossProfitLossSlsOfInvntryAmt>0</GrossProfitLossSlsOfInvntryAmt>
      <TotalRevenueAmt>121352</TotalRevenueAmt>
      <SalariesOtherCompEmplBnftAmt>103939</SalariesOtherCompEmplBnftAmt>
      <FeesAndOtherPymtToIndCntrctAmt>4909</FeesAndOtherPymtToIndCntrctAmt>
      <OccupancyRentUtltsAndMaintAmt>2901</OccupancyRentUtltsAndMaintAmt>
      <OtherExpensesTotalAmt>24941</OtherExpensesTotalAmt>
      <TotalExpensesAmt>136690</TotalExpensesAmt>
      <ExcessOrDeficitForYearAmt>-15338</ExcessOrDeficitForYearAmt>
      <NetAssetsOrFundBalancesBOYAmt>95534</NetAssetsOrFundBalancesBOYAmt>
      <NetAssetsOrFundBalancesEOYAmt>80196</NetAssetsOrFundBalancesEOYAmt>
      <CashSavingsAndInvestmentsGrp>
        <BOYAmt>95819</BOYAmt>
        <EOYAmt>80448</EOYAmt>
      </CashSavingsAndInvestmentsGrp>
      <Form990TotalAssetsGrp>
        <BOYAmt>95819</BOYAmt>
        <EOYAmt>80448</EOYAmt>
      </Form990TotalAssetsGrp>
      <SumOfTotalLiabilitiesGrp>
        <BOYAmt>285</BOYAmt>
        <EOYAmt>252</EOYAmt>
      </SumOfTotalLiabilitiesGrp>
      <NetAssetsOrFundBalancesGrp>
        <BOYAmt>95534</BOYAmt>
        <EOYAmt>80196</EOYAmt>
      </NetAssetsOrFundBalancesGrp>
      <PrimaryExemptPurposeTxt>Public education forums featuring established experts and informed speakers</PrimaryExemptPurposeTxt>
      <ProgramSrvcAccomplishmentGrp>
        <DescriptionProgramSrvcAccomTxt>Hosted forums and produced radio programs discussingart, international relations, science, socialscience, history</DescriptionProgramSrvcAccomTxt>
        <GrantsAndAllocationsAmt>0</GrantsAndAllocationsAmt>
        <ProgramServiceExpensesAmt>130638</ProgramServiceExpensesAmt>
      </ProgramSrvcAccomplishmentGrp>
      <TotalProgramServiceExpensesAmt>130638</TotalProgramServiceExpensesAmt>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>JANE STURTEVANT</PersonNm>
        <TitleTxt>BOARD MEMBER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>TIM WEISKEL</PersonNm>
        <TitleTxt>BOARD MEMBER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>WENDY GRAHAM-COCO</PersonNm>
        <TitleTxt>TREASURER, CLERK</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>5.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>DAVID LEVEILLE</PersonNm>
        <TitleTxt>BOARD MEMBER, WEB MASTER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>3.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>ANDREW KIMBLE</PersonNm>
        <TitleTxt>BOARD MEMBER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>DAVID BRINKMAN</PersonNm>
        <TitleTxt>PRESIDENT</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>3.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>MARY STACK</PersonNm>
        <TitleTxt>PREV EXEC. DIR.BOARD MEM</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>20.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>40764</CompensationAmt>
        <EmployeeBenefitProgramAmt>1500</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>URS GAUCHAT</PersonNm>
        <TitleTxt>BOARD MEMBER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>2.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>RACHELLE QUIMBY</PersonNm>
        <TitleTxt>BOARD MEMBER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>PHILLIP MARTIN</PersonNm>
        <TitleTxt>BOARD MEMBER</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>1.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>0</CompensationAmt>
        <EmployeeBenefitProgramAmt>0</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <OfficerDirectorTrusteeEmplGrp>
        <PersonNm>FREDERIQUE RIGOULOT</PersonNm>
        <TitleTxt>EXEC DIRECTOR</TitleTxt>
        <AverageHrsPerWkDevotedToPosRt>30.00</AverageHrsPerWkDevotedToPosRt>
        <CompensationAmt>48013</CompensationAmt>
        <EmployeeBenefitProgramAmt>6436</EmployeeBenefitProgramAmt>
        <ExpenseAccountOtherAllwncAmt>0</ExpenseAccountOtherAllwncAmt>
      </OfficerDirectorTrusteeEmplGrp>
      <ActivitiesNotPreviouslyRptInd>false</ActivitiesNotPreviouslyRptInd>
      <ChgMadeToOrgnzngDocNotRptInd>false</ChgMadeToOrgnzngDocNotRptInd>
      <OrganizationHadUBIInd>false</OrganizationHadUBIInd>
      <SubjectToProxyTaxInd>false</SubjectToProxyTaxInd>
      <OrganizationDissolvedEtcInd>false</OrganizationDissolvedEtcInd>
      <Form1120PolFiledInd>false</Form1120PolFiledInd>
      <MadeLoansToFromOfficersInd>false</MadeLoansToFromOfficersInd>
      <InitiationFeesAndCapContriAmt>0</InitiationFeesAndCapContriAmt>
      <GrossReceiptsForPublicUseAmt>0</GrossReceiptsForPublicUseAmt>
      <EngagedInExcessBenefitTransInd>false</EngagedInExcessBenefitTransInd>
      <ProhibitedTaxShelterTransInd>false</ProhibitedTaxShelterTransInd>
      <StatesWhereCopyOfReturnIsFldCd>MA</StatesWhereCopyOfReturnIsFldCd>
      <BooksInCareOfDetail>
        <PersonNm>MARY STACK</PersonNm>
        <USAddress>
          <AddressLine1Txt>3 CHURCH STREET</AddressLine1Txt>
          <CityNm>CAMBRIDGE</CityNm>
          <StateAbbreviationCd>MA</StateAbbreviationCd>
          <ZIPCd>02138</ZIPCd>
        </USAddress>
        <PhoneNum>6174952727</PhoneNum>
      </BooksInCareOfDetail>
      <ForeignFinancialAccountInd>false</ForeignFinancialAccountInd>
      <ForeignOfficeInd>false</ForeignOfficeInd>
      <DonorAdvisedFndsInd>false</DonorAdvisedFndsInd>
      <OperateHospitalInd>false</OperateHospitalInd>
      <TanningServicesProvidedInd>false</TanningServicesProvidedInd>
      <RelatedOrganizationCtrlEntInd>false</RelatedOrganizationCtrlEntInd>
      <TransactionWithControlEntInd>false</TransactionWithControlEntInd>
      <PoliticalCampaignActyInd>false</PoliticalCampaignActyInd>
      <LobbyingActivitiesInd>false</LobbyingActivitiesInd>
      <SchoolOperatingInd>false</SchoolOperatingInd>
      <TrnsfrExmptNonChrtblRltdOrgInd>false</TrnsfrExmptNonChrtblRltdOrgInd>
      <PartVIOfCompOfHghstPdEmplTxt>NONE</PartVIOfCompOfHghstPdEmplTxt>
      <PartVIHghstPdCntrctProfSrvcTxt>NONE</PartVIHghstPdCntrctProfSrvcTxt>
      <FiledScheduleAInd>true</FiledScheduleAInd>
    </IRS990EZ>
    <IRS990ScheduleA documentId="IRS990ScheduleA-01" softwareId="25022686">
      <PubliclySupportedOrg509a2Ind>X</PubliclySupportedOrg509a2Ind>
      <OtherSupportSumAmt>0</OtherSupportSumAmt>
      <PublicSupportCY170Pct>0</PublicSupportCY170Pct>
      <GiftsGrantsContrisRcvd509Grp>
        <CurrentTaxYearMinus4YearsAmt>111716</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>79749</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>140752</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>110534</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>121352</CurrentTaxYearAmt>
        <TotalAmt>564103</TotalAmt>
      </GiftsGrantsContrisRcvd509Grp>
      <GrossReceiptsAdmissionsGrp>
        <CurrentTaxYearMinus4YearsAmt>0</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>384</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>0</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>0</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>0</CurrentTaxYearAmt>
        <TotalAmt>384</TotalAmt>
      </GrossReceiptsAdmissionsGrp>
      <GrossReceiptsNonUnrltBusGrp>
        <TotalAmt>0</TotalAmt>
      </GrossReceiptsNonUnrltBusGrp>
      <TaxRevLeviedOrgnztnlBnft509Grp>
        <TotalAmt>0</TotalAmt>
      </TaxRevLeviedOrgnztnlBnft509Grp>
      <Total509Grp>
        <CurrentTaxYearMinus4YearsAmt>111716</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>80133</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>140752</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>110534</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>121352</CurrentTaxYearAmt>
        <TotalAmt>564487</TotalAmt>
      </Total509Grp>
      <AmountsRcvdDsqlfyPersonGrp>
        <TotalAmt>0</TotalAmt>
      </AmountsRcvdDsqlfyPersonGrp>
      <SubstantialContributorsAmtGrp>
        <TotalAmt>0</TotalAmt>
      </SubstantialContributorsAmtGrp>
      <SubstAndDsqlfyPrsnsTotGrp>
        <TotalAmt>0</TotalAmt>
      </SubstAndDsqlfyPrsnsTotGrp>
      <PublicSupportTotal509Amt>564487</PublicSupportTotal509Amt>
      <GrossInvestmentIncome509Grp>
        <CurrentTaxYearMinus4YearsAmt>0</CurrentTaxYearMinus4YearsAmt>
        <TotalAmt>0</TotalAmt>
      </GrossInvestmentIncome509Grp>
      <InvestmentIncomeAndUBTIGrp>
        <CurrentTaxYearMinus4YearsAmt>0</CurrentTaxYearMinus4YearsAmt>
        <TotalAmt>0</TotalAmt>
      </InvestmentIncomeAndUBTIGrp>
      <TotalSupportCalendarYearGrp>
        <CurrentTaxYearMinus4YearsAmt>111716</CurrentTaxYearMinus4YearsAmt>
        <CurrentTaxYearMinus3YearsAmt>80133</CurrentTaxYearMinus3YearsAmt>
        <CurrentTaxYearMinus2YearsAmt>140752</CurrentTaxYearMinus2YearsAmt>
        <CurrentTaxYearMinus1YearAmt>110534</CurrentTaxYearMinus1YearAmt>
        <CurrentTaxYearAmt>121352</CurrentTaxYearAmt>
        <TotalAmt>564487</TotalAmt>
      </TotalSupportCalendarYearGrp>
      <PublicSupportCY509Pct>1.00000</PublicSupportCY509Pct>
      <PublicSupportPY509Pct>0.96820</PublicSupportPY509Pct>
      <InvestmentIncomeCYPct>0.00000</InvestmentIncomeCYPct>
      <InvestmentIncomePYPct>0.00000</InvestmentIncomePYPct>
      <ThirtyThrPctSuprtTestsCY509Ind>X</ThirtyThrPctSuprtTestsCY509Ind>
    </IRS990ScheduleA>
    <IRS990ScheduleB documentId="IRS990ScheduleB-01">
      <ContributorInformationGrp>
        <ContributorNum>RESTRICTED</ContributorNum>
        <ContributorBusinessName>
          <BusinessNameLine1>RESTRICTED</BusinessNameLine1>
        </ContributorBusinessName>
        <ContributorUSAddress>
          <AddressLine1>RESTRICTED</AddressLine1>
          <AddressLine2>RESTRICTED</AddressLine2>
          <City>RESTRICTED</City>
          <State>RESTRICTED</State>
          <ZIPCode>RESTRICTED</ZIPCode>
        </ContributorUSAddress>
        <TotalContributionsAmt>RESTRICTED</TotalContributionsAmt>
      </ContributorInformationGrp>
    </IRS990ScheduleB>
    <IRS990ScheduleO documentId="IRS990ScheduleO-01" softwareId="25022686">
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>INSURANCE 3981.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>OFFICE, AND ADMINISTRATIVE COSTS 3123.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>RADIO TRANSMISSION COSTS, NPR, RECORDINGS 3268.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>PROGRAM WEB AND DEVELOPMENT COSTS 13852.</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>BANK AND PAYROLL FEES</ExplanationTxt>
      </SupplementalInformationDetail>
      <SupplementalInformationDetail>
        <FormAndLineReferenceDesc>Form 990EZ, Part I, Line 16</FormAndLineReferenceDesc>
        <ExplanationTxt>DUES AND SUBSCRIPTIONS 717.</ExplanationTxt>
      </SupplementalInformationDetail>
    </IRS990ScheduleO>
  </ReturnData>
</Return>