<SEC-DOCUMENT>0000950170-25-012568.txt : 20250203
<SEC-HEADER>0000950170-25-012568.hdr.sgml : 20250203
<ACCEPTANCE-DATETIME>20250203183853
ACCESSION NUMBER:		0000950170-25-012568
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250203
FILED AS OF DATE:		20250203
DATE AS OF CHANGE:		20250203

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Doebele Robert
		CENTRAL INDEX KEY:			0001856681
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-41989
		FILM NUMBER:		25584228

	MAIL ADDRESS:	
		STREET 1:		8000 JARVIS AVENUE
		STREET 2:		SUITE 204
		CITY:			NEWARK
		STATE:			CA
		ZIP:			94560

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Boundless Bio, Inc.
		CENTRAL INDEX KEY:			0001782303
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				830751369
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		10955 ALEXANDRIA WAY
		STREET 2:		SUITE 100
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		(858) 766-9912

	MAIL ADDRESS:	
		STREET 1:		10955 ALEXANDRIA WAY
		STREET 2:		SUITE 100
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>ownership.xml
<DESCRIPTION>4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-02-03</periodOfReport>

    <issuer>
        <issuerCik>0001782303</issuerCik>
        <issuerName>Boundless Bio, Inc.</issuerName>
        <issuerTradingSymbol>BOLD</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001856681</rptOwnerCik>
            <rptOwnerName>Doebele Robert</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BOUNDLESS BIO, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>10955 ALEXANDRIA WAY, SUITE 100</rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92121</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Chief Medical Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>false</aff10b5One>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.23</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2025-02-03</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>180000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2035-02-03</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>180000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>180000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option shall vest over a period of four years, with 25% of the shares subject to the option vesting on February 3, 2026, and the remaining shares subject to the option vesting in 36 equal monthly installments thereafter, subject to continued employment or service to the issuer on each such vesting date.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Jessica Oien, Attorney-in- Fact for Robert Doebele.</signatureName>
        <signatureDate>2025-02-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
