content: <?xml version="1.0" encoding="UTF-8"?><edgarSubmission xmlns="http://www.sec.gov/edgar/ownership" xmlns:com="http://www.sec.gov/edgar/common">
    <headerData>
      <submissionType>144</submissionType>
      <filerInfo>
        <filer>
          <filerCredentials>
            <cik>0001341358</cik>
            <ccc>XXXXXXXX</ccc>
          </filerCredentials>
        </filer>
        <liveTestFlag>LIVE</liveTestFlag>
  
  
      </filerInfo>
    </headerData>
    <formData>
      <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>Carey Charles P</nameOfPersonForWhoseAccountTheSecuritiesAreToBeSold>
        <relationshipsToIssuer>
          <relationshipToIssuer>Director</relationshipToIssuer>
        </relationshipsToIssuer>
      </issuerInfo>
      <securitiesInformation>
        <securitiesClassTitle>Common</securitiesClassTitle>
        <brokerOrMarketmakerDetails>
          <name>Pershing Advisor Solutions</name>
          <address>
            <com:street1>95 Christopher Columbus Drive</com:street1>
            <com:city>Jersey City</com:city>
            <com:stateOrCountry>NJ</com:stateOrCountry>
            <com:zipCode>07399</com:zipCode>
          </address>
        </brokerOrMarketmakerDetails>
        <noOfUnitsSold>3000</noOfUnitsSold>
        <aggregateMarketValue>799800.00</aggregateMarketValue>
        <noOfUnitsOutstanding>360360000</noOfUnitsOutstanding>
        <approxSaleDate>05/15/2025</approxSaleDate>
        <securitiesExchangeName>NASDAQ</securitiesExchangeName>
      </securitiesInformation>
      <securitiesToBeSold>
        <securitiesClassTitle>Common Stock</securitiesClassTitle>
        <acquiredDate>07/12/2007</acquiredDate>
        <natureOfAcquisitionTransaction>Received in exchange for shares of CBOT Holdings Inc. (common stock) in connection with the merger of CBOT Holdings with and into Chicago Mercantile Exchange Holdings Inc.</natureOfAcquisitionTransaction>
        <nameOfPersonfromWhomAcquired>Issuer</nameOfPersonfromWhomAcquired>
        <isGiftTransaction>N</isGiftTransaction>
        <amountOfSecuritiesAcquired>12767</amountOfSecuritiesAcquired>
        <paymentDate>07/12/2007</paymentDate>
        <natureOfPayment>Merger Consideration</natureOfPayment>
      </securitiesToBeSold>
      <nothingToReportFlagOnSecuritiesSoldInPast3Months>Y</nothingToReportFlagOnSecuritiesSoldInPast3Months>
      <noticeSignature>
        <noticeDate>05/15/2025</noticeDate>
        <signature>Charles Carey</signature>
      </noticeSignature>
    </formData>
  </edgarSubmission>
metadata_documents: [{"type": "144", "sequence": "1", "filename": "primary_doc.xml", "secsgml_size_bytes": 2877}]
text: 144
  0001341358
  XXXXXXXX
  LIVE
  0001156375
  CME GROUP INC.
  001-31553
  20 S. WACKER DR.
  CHICAGO
  IL
  60606
  3129301000
  Carey Charles P
  Director
  Common
  Pershing Advisor Solutions
  95 Christopher Columbus Drive
  Jersey City
  NJ
  07399
  3000
  799800.00
  360360000
  05/15/2025
  NASDAQ
  Common Stock
  07/12/2007
  Received in exchange for shares of CBOT Holdings Inc. (common stock) in connection with the merger of CBOT Holdings with and into Chicago Mercantile Exchange Holdings Inc.
  Issuer
  N
  12767
  07/12/2007
  Merger Consideration
  Y
  05/15/2025
  Charles Carey