Boardroom Alpha
Boardroom Alpha
ATRA · Additional Proxy Materials (DEFA14A) · Filed April 24, 2026

Atara Biotherapeutics Inc — Additional Proxy Materials (DEFA14A)

Form
DEFA14A
Filed
April 24, 2026
Ticker
ATRA
Accession
0001193125-26-177280
Boardroom Alpha · Filing insights

Atara Biotherapeutics' proxy seeks two director nominees, an advisory exec compensation vote, equity-plan share increase, and audit ratification; board recommends For all items.

About Atara Biotherapeutics Inc
Market cap
$89M
1Y TSR
+7.0%
3Y TSR
−41.6%
Board grade
C
Sector
Healthcare
CEO
Anhco Nguyen
Last annual meeting: Jun 9, 2026 · View full Atara Biotherapeutics Inc profile →
DEFA14A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a)

of the Securities Exchange Act of 1934

(Amendment No.__)

Filed by the Registrant

Filed by a Party other than the Registrant

Check the appropriate box:

Preliminary Proxy Statement

Confidential, for Use of the Commission only (as permitted by Rule 14a-6(e)(2))

Definitive Proxy Statement

Definitive Additional Materials

Soliciting Material Pursuant to § 240.14a-12

Atara Biotherapeutics, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if Other Than the Registrant)

Payment of Filing Fee (Check the appropriate box):

No fee required.

Fee paid previously with preliminary materials.

Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.


 


 

img54495394_0.jpg

Your Vote Counts! ATARA BIOTHERAPEUTICS, INC. 2026 Annual Meeting Vote by June 8, 2026 11:59 PM ET ATARA BIOTHERAPEUTICS, INC. 1280 RANCHO CONEJO BOULEVARD THOUSAND OAKS, CA 91320 V92806-P48060 You invested in ATARA BIOTHERAPEUTICS, INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy materials for the stockholder meeting to be held on June 9, 2026. Get informed before you vote View the Notice and Proxy Statement and 2025 Annual Report on Form 10-K online OR you can receive a free paper or email copy of the material(s) by requesting prior to May 26, 2026. If you would like to request a copy of the material(s) for this and/or future stockholder meetings, you may (1) visit www.ProxyVote.com, (2) call 1-800-579-1639 or (3) send an email to sendmaterial@proxyvote.com. If sending an email, please include your control number (indicated below) in the subject line. Unless requested, you will not otherwise receive a paper or email copy. For complete information and to vote, visit www.ProxyVote.com Control # Smartphone users Point your camera here and vote without entering a control number Vote Virtually at the Meeting* June 9, 2026 9:00 AM Pacific Time Virtually at: www.virtualshareholdermeeting.com/ATRA2026*Please check the meeting materials for any special requirements for meeting attendance.


 

img54495394_1.jpg

Vote at www.ProxyVote.comTHIS IS NOT A VOTABLE BALLOT This is an overview of the proposals being presented at the upcoming stockholder meeting. Please follow the instructions on the reverse side to vote these important matters. Voting Items Board Recommends 1. Election of Directors Nominees: 1a. AnhCo Nguyen, Ph.D. 1b. Nachi Subramanian 2. To approve, on an advisory basis, the compensation of the Company’s named executive officers, as disclosed in the Proxy Statement. 3. To approve the first amendment to our 2024 Equity Incentive Plan to increase the number of shares of common stock reserved for issuance thereunder by 400,000. 4. To ratify the selection of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026. NOTE: Such other matters that may properly come before the meeting or any adjournment or postponement thereof will be voted on by the proxy holders in their discretion. For For For For For Prefer to receive an email instead? While voting on www.ProxyVote.com, be sure to click “Delivery Settings”. V92807-P48060


From this filing to the vote

Forecast every director vote the day the proxy files.

Meeting Forecast scores each director up for re-election + every contested situation, rebuilt daily across 6,000+ U.S. public companies. The same model that called the LULU contested proxy lives on every meeting you see here.

Independent — issuer-pays-free, ideology-free, U.S.-owned.

More filings

Other filings from Atara Biotherapeutics Inc (ATRA)

Reference

Frequently asked questions

When did Atara Biotherapeutics Inc file this DEFA14A?
Atara Biotherapeutics Inc (ATRA) filed this Additional Proxy Materials (DEFA14A) with the SEC on April 24, 2026. The accession number assigned by EDGAR is 0001193125-26-177280.
What does a DEFA14A disclose?
DEFA14A is additional definitive proxy soliciting material filed in connection with a shareholder meeting — supplemental letters, slides, or amendments issued after the main proxy statement.
What is the key takeaway from this filing?
Atara Biotherapeutics' proxy seeks two director nominees, an advisory exec compensation vote, equity-plan share increase, and audit ratification; board recommends For all items. This is Boardroom Alpha's one-line summary of the additional proxy materials; see the full filing text above for the formal disclosure.
Where can I find Atara Biotherapeutics Inc's prior proxy statements on EDGAR?
The SEC EDGAR browser lists every DEFA14A Atara Biotherapeutics Inc has filed under CIK 1604464, sortable by date. Use the "View on SEC EDGAR" link in the page header, or browse directly via https://www.sec.gov/cgi-bin/browse-edgar.
Disclaimer

The opinions and information contained herein have been obtained or derived from sources believed to be reliable, but Boardroom Alpha cannot guarantee its accuracy and completeness, and that of the opinions based thereon.

This report contains opinions and is provided for informational purposes only – it does not constitute investment, legal or tax advice. You should not rely solely upon the research herein for purposes of transacting securities or other investments, and you are encouraged to conduct your own research and due diligence, and to seek the advice of a qualified securities professional before you make any investment.

None of the information contained in this report constitutes, or is intended to constitute a recommendation by Boardroom Alpha of any particular security or trading strategy or a determination by Boardroom Alpha that any security or trading strategy is suitable for any specific person. To the extent any of the information contained herein may be deemed to be investment advice, such information is impersonal and not tailored to the investment needs of any specific person.

No representation or warranty, expressed or implied, is made on behalf of Boardroom Alpha as to the accuracy or completeness of the information contained herein. Boardroom Alpha does not accept any liability for any direct, indirect or consequential loss or damage suffered by any person as a result of relying on all or any part of this research and any liability is expressly disclaimed.

Full disclaimer