<SEC-DOCUMENT>0001156375-24-000016.txt : 20240315
<SEC-HEADER>0001156375-24-000016.hdr.sgml : 20240315
<ACCEPTANCE-DATETIME>20240315162012
ACCESSION NUMBER:		0001156375-24-000016
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20231231
FILED AS OF DATE:		20240315
DATE AS OF CHANGE:		20240315

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Carey Charles P
		CENTRAL INDEX KEY:			0001341358
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31553
		FILM NUMBER:		24755079

	MAIL ADDRESS:	
		STREET 1:		20 S. WACKER DRIVE
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CME GROUP INC.
		CENTRAL INDEX KEY:			0001156375
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY & COMMODITY BROKERS, DEALERS, EXCHANGES & SERVICES [6200]
		ORGANIZATION NAME:           	02 Finance
		IRS NUMBER:				364459170
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		20 S. WACKER DR.
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3129301000

	MAIL ADDRESS:	
		STREET 1:		20 S. WACKER DR.
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CHICAGO MERCANTILE EXCHANGE HOLDINGS INC
		DATE OF NAME CHANGE:	20010802
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>wk-form5_1710534001.xml
<DESCRIPTION>FORM 5
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2023-12-31</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0001156375</issuerCik>
        <issuerName>CME GROUP INC.</issuerName>
        <issuerTradingSymbol>CME</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001341358</rptOwnerCik>
            <rptOwnerName>Carey Charles P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>20 S. WACKER DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock Class A</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10163</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock Class A</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0.375</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Partnership</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock Class A</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>185</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Firm</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock, Series B-2</value>
            </securityTitle>
            <transactionDate>
                <value>2023-10-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>L</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>211.93</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Partnership</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock, Series B-1</value>
            </securityTitle>
            <transactionDate>
                <value>2023-10-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>L</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>215.76</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Partnership</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock, Series B-3</value>
            </securityTitle>
            <transactionDate>
                <value>2023-10-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>L</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>215.76</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Partnership</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock, Series B-4</value>
            </securityTitle>
            <transactionDate>
                <value>2023-10-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value>L</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>216.09</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Partnership</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">This Form 5 is being filed to reflect an update to Mr. Carey's ownership of Class B shares that were previously reported as being indirectly owned by Mr. Carey in connection with his ownership of HC Technologies.  Subsequent to the sale of HC Technologies' assets, one Class B-2 share was sold on  October 6, 2023.  The Class B common stock of CME Group Inc. is not listed on a national securities exchange or traded in an organized over-the-counter market. Each class of the Class B common stock is associated with a membership in a specific division of the exchange. We assume that because the Class B shares have the same equitable interest in our earnings and the same dividend payments as our Class A shares, that if reported separately from the associated trading rights, they would have the same market price as our Class A common stock.  The closing price for our Class A common stock on October 6, 2023 was $211.93.</footnote>
        <footnote id="F2">This Form 5 is being filed to reflect an update to Mr. Carey's ownership of Class B shares that were previously reported as being indirectly owned by Mr. Carey in connection with his ownership of HC Technologies. Subsequent to the sale of HC Technologies' assets,  one Class B-1 share and one Class B-3 share were sold on October 9, 2023.  The Class B common stock of CME Group Inc. is not listed on a national securities exchange or traded in an organized over-the-counter market. Each class of the Class B common stock is associated with a membership in a specific division of the exchange. We assume that because the Class B shares have the same equitable interest in our earnings and the same dividend payments as our Class A shares, that if reported separately from the associated trading rights, they would have the same market price as our Class A common stock.  The closing price for our Class A common stock on October 9, 2023 was $215.76</footnote>
        <footnote id="F3">This Form 5 is being filed to reflect an update to Mr. Carey's ownership of Class B shares that were previously reported as being indirectly owned by Mr. Carey in connection with his ownership of HC Technologies. Subsequent to the sale of HC Technologies' assets, one Class B-4 share was sold on October 10, 2023.  The Class B common stock of CME Group Inc. is not listed on a national securities exchange or traded in an organized over-the-counter market. Each class of the Class B common stock is associated with a membership in a specific division of the exchange. We assume that because the Class B shares have the same equitable interest in our earnings and the same dividend payments as our Class A shares, that if reported separately from the associated trading rights, they would have the same market price as our Class A common stock.  The closing price for our Class A common stock on October 10, 2023 was $216.09.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Jenelle Chalmers	 For: Charles P. Carey</signatureName>
        <signatureDate>2024-03-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
