<SEC-DOCUMENT>0002011286-25-000087.txt : 20250307
<SEC-HEADER>0002011286-25-000087.hdr.sgml : 20250307
<ACCEPTANCE-DATETIME>20250307163828
ACCESSION NUMBER:		0002011286-25-000087
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250305
FILED AS OF DATE:		20250307
DATE AS OF CHANGE:		20250307

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			EBERHART RALPH E
		CENTRAL INDEX KEY:			0001409312
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42176
		FILM NUMBER:		25720702

	MAIL ADDRESS:	
		STREET 1:		909 N. WASHINGTON STREET
		CITY:			ALEXANDRIA
		STATE:			VA
		ZIP:			22314

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Amentum Holdings, Inc.
		CENTRAL INDEX KEY:			0002011286
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-BUSINESS SERVICES, NEC [7389]
		ORGANIZATION NAME:           	07 Trade & Services
		IRS NUMBER:				990622272
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1003

	BUSINESS ADDRESS:	
		STREET 1:		4800 WESTFIELDS BOULEVARD
		STREET 2:		SUITE 400
		CITY:			CHANTILLY
		STATE:			VA
		ZIP:			20151
		BUSINESS PHONE:		7035790410

	MAIL ADDRESS:	
		STREET 1:		4800 WESTFIELDS BOULEVARD
		STREET 2:		SUITE 400
		CITY:			CHANTILLY
		STATE:			VA
		ZIP:			20151

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Amazon Holdco Inc.
		DATE OF NAME CHANGE:	20240208
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1741383503.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-03-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0002011286</issuerCik>
        <issuerName>Amentum Holdings, Inc.</issuerName>
        <issuerTradingSymbol>AMTM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001409312</rptOwnerCik>
            <rptOwnerName>EBERHART RALPH E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AMENTUM HOLDINGS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4800 WESTFIELDS BOULEVARD, SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>CHANTILLY</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>20151</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-09-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value>E</value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>26439</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>26439</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
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            <transactionAmounts>
                <transactionShares>
                    <value>3447</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>29886</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3447</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3447</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Represents securities received in a pro-rata distribution in-kind by Jacobs Solutions Inc. for no consideration.</footnote>
        <footnote id="F2">Represents distribution of AMTM common stock upon vesting of restricted stock units.</footnote>
        <footnote id="F3">Each restricted stock unit represents a contingent right to receive one share of AMTM common stock.</footnote>
        <footnote id="F4">The restricted stock units awarded vested on March 5, 2025.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Paul W. Cobb, Jr.
Attorney-in-fact</signatureName>
        <signatureDate>2025-03-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
