As filed with the Securities and Exchange Commission on June 12, 2026

Registration No. 333-    

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8 

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

ATARA BIOTHERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

1280 Rancho Conejo Boulevard

Thousand Oaks, California 91320

(Address, including zip code, of Registrant’s principal executive offices)

Atara Biotherapeutics, Inc. 2024 Equity Incentive Plan, as amended

(Full title of the plan)

AnhCo Nguyen, Ph.D.

President and Chief Executive Officer

1280 Rancho Conejo Boulevard

Thousand Oaks, California 91320

(805) 623-4211 

(Name, address, and telephone number, including area code, of agent for service)

Copies to:

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

EXPLANATORY NOTE

This Registration Statement on Form S-8 (this “Registration Statement”) is being filed by Atara Biotherapeutics, Inc., a Delaware corporation (the “Registrant”), for the purpose of registering an additional 400,000 shares of Registrant common stock, par value $0.0001 per share (the “Common Stock”) that were reserved for issuance under the Atara Biotherapeutics, Inc. 2024 Equity Incentive Plan, as amended (the “Plan”). This Registration Statement hereby incorporates by reference the contents of the Registrant's prior Registration Statements on Form S-8 filed with the Securities and Exchange Commission (the “SEC”) on June 11, 2024 (SEC File No. 333-280125) and January 17, 2025 (SEC File No. 333-284338) (the “Prior Registration Statements”) registering shares of Common Stock issuable under the Plan. This Registration Statement relates to securities of the same class as those to which the Prior Registration Statements relate and is submitted in accordance with General Instruction E of Form S-8 regarding Registration of Additional Securities. Pursuant to General Instruction E of Form S-8, the contents of the Prior Registration Statements are incorporated herein by reference and made part of this Registration Statement, except for Items 3 and 8, which are being updated by this Registration Statement.

PART I

INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

All information required by Part I to be contained in the prospectus is omitted from this Registration Statement in accordance with the explanatory note to Part I of Form S-8 and Rule 428 under the Securities Act of 1933, as amended (the “Securities Act”). Documents containing the information required by Part I of the Registration Statement will be sent or given to Plan participants as specified by Rule 428(b)(1) of the Securities Act.

PART II

ITEM 3. INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

The following documents filed by the Registrant with the SEC are incorporated by reference into this Registration Statement:

ITEM 8. EXHIBITS 

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Thousand Oaks, State of California, on this 12 day of June, 2026.

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints AnhCo Thieu Nguyen, Ph.D., Yanina Grant-Huerta and John Chao, and each of them, as his or her true and lawful attorneys-in-fact and agents, each with the full power of substitution, for him or her and in his or her name, place or stead, in any and all capacities, to sign any and all amendments to this Registration Statement (including post-effective amendments), and to sign any registration statement for the same offering covered by this Registration Statement that is to be effective upon filing pursuant to Rule 462(b) promulgated under the Securities Act of 1933, as amended, and all post-effective amendments thereto, and to file the same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or their, his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

II-3

ATTACHMENTS / EXHIBITS

FIRST AMENDMENT TO THE ATARA BIOTHERAPEUTICS, INC. 2024 EQUITY INCENTIVE PLAN

OPINION OF SIDLEY AUSTIN LLP

CONSENT OF DELOITTE & TOUCHE LLP, INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

CALCULATION OF FILING FEE TABLE

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