<SEC-DOCUMENT>0000905148-26-001143.txt : 20260304
<SEC-HEADER>0000905148-26-001143.hdr.sgml : 20260304
<ACCEPTANCE-DATETIME>20260304162809
ACCESSION NUMBER:		0000905148-26-001143
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20260302
FILED AS OF DATE:		20260304
DATE AS OF CHANGE:		20260304

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Nguyen AnhCo
		CENTRAL INDEX KEY:			0001977970
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-36548
		FILM NUMBER:		26721765

	MAIL ADDRESS:	
		STREET 1:		2380 CONEJO SPECTRUM ST
		STREET 2:		SUITE 200
		CITY:			THOUSAND OAKS
		STATE:			CA
		ZIP:			91320

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Atara Biotherapeutics, Inc.
		CENTRAL INDEX KEY:			0001604464
		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
		ORGANIZATION NAME:           	03 Life Sciences
		EIN:				460920988
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1280 RANCHO CONEJO BLVD
		CITY:			THOUSAND OAKS
		STATE:			CA
		ZIP:			91320
		BUSINESS PHONE:		805-623-4211

	MAIL ADDRESS:	
		STREET 1:		1280 RANCHO CONEJO BLVD
		CITY:			THOUSAND OAKS
		STATE:			CA
		ZIP:			91320
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form4.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2026-03-02</periodOfReport>

    <issuer>
        <issuerCik>0001604464</issuerCik>
        <issuerName>Atara Biotherapeutics, Inc.</issuerName>
        <issuerTradingSymbol>ATRA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001977970</rptOwnerCik>
            <rptOwnerName>Nguyen AnhCo</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ATARA BIOTHERAPEUTICS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>1280 RANCHO CONEJO BOULEVARD</rptOwnerStreet2>
            <rptOwnerCity>THOUSAND OAKS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>91320</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>false</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>198</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.079</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>64776</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>58</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.08</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>64718</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1298</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.086</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>63420</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2026-03-02</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1442</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>5.087</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>61978</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement.</footnote>
        <footnote id="F2">The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on March 2, 2026 on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employees.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ John Chao, Attorney-in-Fact for AnhCo Nguyen</signatureName>
        <signatureDate>2026-03-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
