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        <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>MFS International Value Fund</name>
        <lei>7540QFSKYNTDFH7HAK24</lei>
        <title>MFS International Value Fund</title>
        <cusip>552746349</cusip>
        <identifiers>
          <isin value="US5527463492"/>
        </identifiers>
        <balance>307143.12500000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>12955297.01000000</valUSD>
        <pctVal>2.987121366059</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>MFS Growth Fund</name>
        <lei>K4ZYIH3WSXKUSPKIPM59</lei>
        <title>MFS Growth Fund</title>
        <cusip>552985673</cusip>
        <identifiers>
          <isin value="US5529856735"/>
        </identifiers>
        <balance>198318.14100000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>25329192.97000000</valUSD>
        <pctVal>5.840188260241</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>MFS Mid Cap Growth Fund</name>
        <lei>XPX0WXKIO6CLKBLYF666</lei>
        <title>MFS Mid Cap Growth Fund</title>
        <cusip>552987554</cusip>
        <identifiers>
          <isin value="US5529875545"/>
        </identifiers>
        <balance>982003.02200000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>20926484.40000000</valUSD>
        <pctVal>4.825049446532</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>MFS New Discovery Value Fund</name>
        <lei>LRMRW30Z8FYTIFW1W860</lei>
        <title>MFS New Discovery Value Fund</title>
        <cusip>552982696</cusip>
        <identifiers>
          <isin value="US5529826969"/>
        </identifiers>
        <balance>411821.90900000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>5201310.71000000</valUSD>
        <pctVal>1.199273651647</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>MFS New Discovery Fund</name>
        <lei>ZVEMRLDGMDO1D1VDSU87</lei>
        <title>MFS New Discovery Fund</title>
        <cusip>55273H346</cusip>
        <identifiers>
          <isin value="US55273H3460"/>
        </identifiers>
        <balance>176433.90800000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>5210093.30000000</valUSD>
        <pctVal>1.201298665988</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>MFS Inflation Adjusted Bond Fund</name>
        <lei>VOHO802M9IKG3IZTEN75</lei>
        <title>MFS Inflation Adjusted Bond Fund</title>
        <cusip>55274K884</cusip>
        <identifiers>
          <isin value="US55274K8844"/>
        </identifiers>
        <balance>1389475.95600000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>15075814.12000000</valUSD>
        <pctVal>3.476052029825</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>MFS High Income Fund</name>
        <lei>DMVGFZCV67YA34LSI126</lei>
        <title>MFS High Income Fund</title>
        <cusip>552984684</cusip>
        <identifiers>
          <isin value="US5529846843"/>
        </identifiers>
        <balance>3023542.62100000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>9524159.26000000</valUSD>
        <pctVal>2.195999026293</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>MFS Value Fund</name>
        <lei>HV6C0RMURVKFUQ3UTB42</lei>
        <title>MFS Value Fund</title>
        <cusip>55273H353</cusip>
        <identifiers>
          <isin value="US55273H3536"/>
        </identifiers>
        <balance>670170.13800000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>24983942.74000000</valUSD>
        <pctVal>5.760583420778</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>MFS Blended Research Emerging Markets Equity Fund</name>
        <lei>549300N4Y1QEM5QDU861</lei>
        <title>MFS Blended Research Emerging Markets Equity Fund</title>
        <cusip>552987240</cusip>
        <identifiers>
          <isin value="US5529872401"/>
        </identifiers>
        <balance>298500.87800000</balance>
        <units>NS</units>
        <curCd>USD</curCd>
        <valUSD>3313359.75000000</valUSD>
        <pctVal>0.763966097807</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>
    </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>2020-05-14</ncom:dateSigned>
      <ncom:nameOfApplicant>MFS SERIES TRUST XII</ncom:nameOfApplicant>
      <ncom:signature>Kasey Phillips</ncom:signature>
      <ncom:signerName>Kasey Phillips</ncom:signerName>
      <ncom:title>Assistant Treasurer</ncom:title>
    </signature>
  </formData>
</edgarSubmission>
