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        <name>Calvert Emerging Markets Advancement Fund</name>
        <lei>549300OOWWGW13TF0P06</lei>
        <title>Calvert Emerging Markets Advancement Fund</title>
        <cusip>131649717</cusip>
        <identifiers>
          <isin value="US1316497171"/>
        </identifiers>
        <balance>282204.53000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>4453187.51000000</valUSD>
        <pctVal>2.022046044352</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Calvert International Equity Fund</name>
        <lei>549300DYXGATLWKZ1990</lei>
        <title>Calvert International Equity Fund</title>
        <cusip>131649741</cusip>
        <identifiers>
          <isin value="US1316497411"/>
        </identifiers>
        <balance>226864.60000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>5760092.30000000</valUSD>
        <pctVal>2.615468543412</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Calvert International Opportunities Fund</name>
        <lei>549300125QOYCBC7IB51</lei>
        <title>Calvert International Opportunities Fund</title>
        <cusip>131649758</cusip>
        <identifiers>
          <isin value="US1316497585"/>
        </identifiers>
        <balance>853.05000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>14578.62000000</valUSD>
        <pctVal>0.006619672052</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Calvert Emerging Markets Equity Fund</name>
        <lei>549300L4S5NY62FOKA38</lei>
        <title>Calvert Emerging Markets Equity Fund</title>
        <cusip>131649766</cusip>
        <identifiers>
          <isin value="US1316497668"/>
        </identifiers>
        <balance>82608.66000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>1949564.26000000</valUSD>
        <pctVal>0.885233036177</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>EC</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Morgan Stanley &amp; Co. LLC</name>
        <lei>549300BI6Y5SI6BYPB26</lei>
        <title>Morgan Stanley Institutional Liquidity Funds - Government Portfolio</title>
        <cusip>61747C707</cusip>
        <identifiers>
          <isin value="US61747C7074"/>
        </identifiers>
        <balance>1782072.23000000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>1782072.23000000</valUSD>
        <pctVal>0.809180411857</pctVal>
        <payoffProfile>Long</payoffProfile>
        <assetCat>STIV</assetCat>
        <issuerCat>RF</issuerCat>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Chicago Board of Trade</name>
        <lei>549300EX04Q2QBFQTQ27</lei>
        <title>US LONG BOND(CBT) JUN26</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Bloomberg Identifier" value="BBG01XB0N4P2"/>
        </identifiers>
        <balance>22.00000000</balance>
        <units>NC</units>
        <curCd>USD</curCd>
        <valUSD>-79435.29000000</valUSD>
        <pctVal>-0.03606895365</pctVal>
        <payoffProfile>N/A</payoffProfile>
        <assetCat>DIR</assetCat>
        <issuerConditional desc="derivative" issuerCat="OTHER"/>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <derivativeInfo>
          <futrDeriv derivCat="FUT">
            <counterparties>
              <counterpartyName>Chicago Board of Trade</counterpartyName>
              <counterpartyLei>549300EX04Q2QBFQTQ27</counterpartyLei>
            </counterparties>
            <payOffProf>Long</payOffProf>
            <descRefInstrmnt>
              <indexBasketInfo>
                <indexName>CBOT U.S. Long Bond Futures</indexName>
                <indexIdentifier>USM6 Comdty</indexIdentifier>
              </indexBasketInfo>
            </descRefInstrmnt>
            <expDate>2026-06-18</expDate>
            <notionalAmt>2584685.29000000</notionalAmt>
            <curCd>USD</curCd>
            <unrealizedAppr>-79435.29000000</unrealizedAppr>
          </futrDeriv>
        </derivativeInfo>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
      <invstOrSec>
        <name>Chicago Board of Trade</name>
        <lei>549300EX04Q2QBFQTQ27</lei>
        <title>US ULTRA BOND CBT JUN26</title>
        <cusip>000000000</cusip>
        <identifiers>
          <other otherDesc="Bloomberg Identifier" value="BBG01XB0MZQ3"/>
        </identifiers>
        <balance>27.00000000</balance>
        <units>NC</units>
        <curCd>USD</curCd>
        <valUSD>-104682.24000000</valUSD>
        <pctVal>-0.04753276362</pctVal>
        <payoffProfile>N/A</payoffProfile>
        <assetCat>DIR</assetCat>
        <issuerConditional desc="derivative" issuerCat="OTHER"/>
        <invCountry>US</invCountry>
        <isRestrictedSec>N</isRestrictedSec>

        <fairValLevel>1</fairValLevel>
        <derivativeInfo>
          <futrDeriv derivCat="FUT">
            <counterparties>
              <counterpartyName>Chicago Board of Trade</counterpartyName>
              <counterpartyLei>549300EX04Q2QBFQTQ27</counterpartyLei>
            </counterparties>
            <payOffProf>Long</payOffProf>
            <descRefInstrmnt>
              <indexBasketInfo>
                <indexName>CBOT Ultra Long-Term U.S. Treasury Bond Futures</indexName>
                <indexIdentifier>WNM6 Comdty</indexIdentifier>
              </indexBasketInfo>
            </descRefInstrmnt>
            <expDate>2026-06-18</expDate>
            <notionalAmt>3251869.74000000</notionalAmt>
            <curCd>USD</curCd>
            <unrealizedAppr>-104682.24000000</unrealizedAppr>
          </futrDeriv>
        </derivativeInfo>
        <securityLending>
          <isCashCollateral>N</isCashCollateral>
          <isNonCashCollateral>N</isNonCashCollateral>
          <isLoanByFund>N</isLoanByFund>
        </securityLending>
      </invstOrSec>
    </invstOrSecs>
    <explntrNotes>
      <explntrNote note="Monthly returns presented in Item B.5(a) have been calculated without deducting any applicable sales loads or redemption fees." noteItem="B.5.a"/>
    </explntrNotes>
    <signature>
      <ncom:dateSigned>2026-04-17</ncom:dateSigned>
      <ncom:nameOfApplicant>Calvert Social Investment Fund</ncom:nameOfApplicant>
      <ncom:signature>James Kirchner</ncom:signature>
      <ncom:signerName>James Kirchner</ncom:signerName>
      <ncom:title>Treasurer</ncom:title>
    </signature>
  </formData>
</edgarSubmission>
