<SEC-DOCUMENT>0002011286-25-000062.txt : 20250214
<SEC-HEADER>0002011286-25-000062.hdr.sgml : 20250214
<ACCEPTANCE-DATETIME>20250214181803
ACCESSION NUMBER:		0002011286-25-000062
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250212
FILED AS OF DATE:		20250214
DATE AS OF CHANGE:		20250214

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DEMETRIOU STEVEN J.
		CENTRAL INDEX KEY:			0001173003
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-42176
		FILM NUMBER:		25631624

	MAIL ADDRESS:	
		STREET 1:		25825 SCIENCE PARK DRIVE, SUITE 400
		CITY:			BEACHWOOD
		STATE:			OH
		ZIP:			44102

	FORMER NAME:	
		FORMER CONFORMED NAME:	DEMETRIOU STEVEN J
		DATE OF NAME CHANGE:	20020509

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_1739575076.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-02-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001173003</rptOwnerCik>
            <rptOwnerName>DEMETRIOU STEVEN J.</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>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Chair</officerTitle>
        </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>520893</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>520893</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2025-02-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>20.807</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>620893</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>23550</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></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">The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $20.60 to $21.08, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth herein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Paul W. Cobb, Jr.
Attorney-in-fact</signatureName>
        <signatureDate>2025-02-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
