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      <filer>
        <filerCredentials>
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          <ccc>XXXXXXXX</ccc>
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      <liveTestFlag>LIVE</liveTestFlag>



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    <issuerInfo>
      <issuerCik>0001156375</issuerCik>
      <issuerName>CME GROUP INC.</issuerName>
      <secFileNumber>001-31553</secFileNumber>
      <issuerAddress>
        <com:street1>20 S. WACKER DR.</com:street1>
        <com:city>CHICAGO</com:city>
        <com:stateOrCountry>IL</com:stateOrCountry>
        <com:zipCode>60606</com:zipCode>
      </issuerAddress>
      <issuerContactPhone>3129301000</issuerContactPhone>
      <nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>Sammann Derek</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
      <relationshipsToIssuer>
        <relationshipToIssuer>Officer</relationshipToIssuer>
      </relationshipsToIssuer>
    </issuerInfo>
    <securitiesInformation>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <brokerOrMarketmakerDetails>
        <name>Charles Schwab Corporation</name>
        <address>
          <com:street1>3000 Schwab Way</com:street1>
          <com:city>Westlake</com:city>
          <com:stateOrCountry>TX</com:stateOrCountry>
          <com:zipCode>76262</com:zipCode>
        </address>
      </brokerOrMarketmakerDetails>
      <noOfUnitsSold>931</noOfUnitsSold>
      <aggregateMarketValue>204391.00</aggregateMarketValue>
      <noOfUnitsOutstanding>359989838</noOfUnitsOutstanding>
      <approxSaleDate>12/01/2023</approxSaleDate>
      <securitiesExchangeName>Nasdaq</securitiesExchangeName>
    </securitiesInformation>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>09/15/2011</acquiredDate>
      <natureOfAcquisitionTransaction>Employee Compensation</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>225</amountOfSecuritiesAcquired>
      <paymentDate>09/15/2011</paymentDate>
      <natureOfPayment>Employee Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>09/15/2017</acquiredDate>
      <natureOfAcquisitionTransaction>Employee Compensation</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>185</amountOfSecuritiesAcquired>
      <paymentDate>09/15/2017</paymentDate>
      <natureOfPayment>Employee Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>03/15/2018</acquiredDate>
      <natureOfAcquisitionTransaction>Employee Compensation</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>341</amountOfSecuritiesAcquired>
      <paymentDate>03/15/2018</paymentDate>
      <natureOfPayment>Employee Compensation</natureOfPayment>
    </securitiesToBeSold>
    <securitiesToBeSold>
      <securitiesClassTitle>Common</securitiesClassTitle>
      <acquiredDate>09/14/2020</acquiredDate>
      <natureOfAcquisitionTransaction>Employee Compensation</natureOfAcquisitionTransaction>
      <nameOfPersonfromWhomAcquired>issuer</nameOfPersonfromWhomAcquired>
      <isGiftTransaction>N</isGiftTransaction>
      <amountOfSecuritiesAcquired>180</amountOfSecuritiesAcquired>
      <paymentDate>09/14/2020</paymentDate>
      <natureOfPayment>Employee Compensation</natureOfPayment>
    </securitiesToBeSold>
    <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
    <remarks>Elizabeth A Sammann TTEE Cooper Sammann 2016 Trust / Derek Sammann - Grantor</remarks>
    <noticeSignature>
      <noticeDate>12/01/2023</noticeDate>
      <signature>Derek Sammann</signature>
    </noticeSignature>
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144
0001475318
XXXXXXXX
LIVE
0001156375
CME GROUP INC.
001-31553
20 S. WACKER DR.
CHICAGO
IL
60606
3129301000
Sammann Derek
Officer
Common
Charles Schwab Corporation
3000 Schwab Way
Westlake
TX
76262
931
204391.00
359989838
12/01/2023
Nasdaq
Common
09/15/2011
Employee Compensation
Issuer
N
225
09/15/2011
Employee Compensation
Common
09/15/2017
Employee Compensation
Issuer
N
185
09/15/2017
Employee Compensation
Common
03/15/2018
Employee Compensation
issuer
N
341
03/15/2018
Employee Compensation
Common
09/14/2020
Employee Compensation
issuer
N
180
09/14/2020
Employee Compensation
Y
Elizabeth A Sammann TTEE Cooper Sammann 2016 Trust / Derek Sammann - Grantor
12/01/2023
Derek Sammann