<SEC-DOCUMENT>0001156375-24-000074.txt : 20240501
<SEC-HEADER>0001156375-24-000074.hdr.sgml : 20240501
<ACCEPTANCE-DATETIME>20240501170642
ACCESSION NUMBER:		0001156375-24-000074
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20240429
FILED AS OF DATE:		20240501
DATE AS OF CHANGE:		20240501

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DUFFY TERRENCE A
		CENTRAL INDEX KEY:			0001212809
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31553
		FILM NUMBER:		24903976

	MAIL ADDRESS:	
		STREET 1:		20 S. WACKER DR
		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>4
<SEQUENCE>1
<FILENAME>wk-form4_1714597589.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-04-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001212809</rptOwnerCik>
            <rptOwnerName>DUFFY TERRENCE A</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>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock Class A</value>
            </securityTitle>
            <transactionDate>
                <value>2024-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4076</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>209.52</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>103379</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock Class A</value>
            </securityTitle>
            <transactionDate>
                <value>2024-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10708</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>210.20</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>92671</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock Class A</value>
            </securityTitle>
            <transactionDate>
                <value>2024-04-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>25216</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>211.44</value>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>67455</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in column four is a weighted average price. These shares were sold in multiple transactions at prices ranging from $209.485 to $209.64, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the Staff of the Securities and Exchange Commission, upon request, with full information regarding the number of shares sold at each separate price within this above range.</footnote>
        <footnote id="F2">The price reported in column four is a weighted average price. These shares were sold in multiple transactions at prices ranging from $210.00 to $210.45, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the Staff of the Securities and Exchange Commission, upon request, with full information regarding the number of shares sold at each separate price within this above range.</footnote>
        <footnote id="F3">The price reported in column four is a weighted average price. These shares were sold in multiple transactions at prices ranging from $211.00 to $211.8932, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer or the Staff of the Securities and Exchange Commission, upon request, with full information regarding the number of shares sold at each separate price within this above range.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Margaret Austin Wright for Terrence A. Duffy</signatureName>
        <signatureDate>2024-05-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
