<SEC-DOCUMENT>0001372455-26-000002.txt : 20260312
<SEC-HEADER>0001372455-26-000002.hdr.sgml : 20260312
<ACCEPTANCE-DATETIME>20260312162931
ACCESSION NUMBER:		0001372455-26-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260311
FILED AS OF DATE:		20260312
DATE AS OF CHANGE:		20260312

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Posner Brian S
		CENTRAL INDEX KEY:			0001372455
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16209
		FILM NUMBER:		26748227

	MAIL ADDRESS:	
		STREET 1:		14 CAMBRIDGE CENTER
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02142

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ARCH CAPITAL GROUP LTD.
		CENTRAL INDEX KEY:			0000947484
		STANDARD INDUSTRIAL CLASSIFICATION:	FIRE, MARINE & CASUALTY INSURANCE [6331]
		ORGANIZATION NAME:           	02 Finance
		EIN:				980374481
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		WATERLOO HOUSE, GROUND FLOOR
		STREET 2:		100 PITTS BAY ROAD
		CITY:			PEMBROKE
		STATE:			D0
		ZIP:			HM 08
		BUSINESS PHONE:		441-278-9250

	MAIL ADDRESS:	
		STREET 1:		WATERLOO HOUSE, GROUND FLOOR
		STREET 2:		100 PITTS BAY ROAD
		CITY:			PEMBROKE
		STATE:			D0
		ZIP:			HM 08

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ARCH CAPITAL GROUP LTD
		DATE OF NAME CHANGE:	20000508

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RISK CAPITAL HOLDINGS INC
		DATE OF NAME CHANGE:	19950816

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RISK CAPITAL RE INC
		DATE OF NAME CHANGE:	19950703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1773347368.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000947484</issuerCik>
        <issuerName>ARCH CAPITAL GROUP LTD.</issuerName>
        <issuerTradingSymbol>ACGL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001372455</rptOwnerCik>
            <rptOwnerName>Posner Brian S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>WATERLOO HOUSE, GROUND FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2>100 PITTS BAY ROAD</rptOwnerStreet2>
            <rptOwnerCity>PEMBROKE</rptOwnerCity>
            <rptOwnerState>D0</rptOwnerState>
            <rptOwnerZipCode>HM 08</rptOwnerZipCode>
            <rptOwnerStateDescription>BERMUDA</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Depositary Shares, Series G</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2026-03-11</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.115</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Shares, $.0011 par value per share</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>120104</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Depositary Shares, Series F</value>
                <footnoteId id="F3"/>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Each Depositary Share Represents 1/1,000th interest in a Series G Non-Cumulative Preferred Share.</footnote>
        <footnote id="F2">The price reported is a weighted average sale price. These shares were sold in multiple transactions at prices ranging from $17.1149 to $17.1150. Upon request, the full information regarding the number of shares sold at each separate price within the range will be provided to the issuer, any security holder of the issuer or the staff of the Securities Exchange Commission.</footnote>
        <footnote id="F3">Each Depositary Share Represents 1/1,000th interest in a Series F Non-Cumulative Preferred Share.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Brian S. Posner</signatureName>
        <signatureDate>2026-03-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
