As of November 6, 2026, Atara Biotherapeutics, Inc. is a publicly traded company (Nasdaq: ATRA). The largest holder reporting an active stake on Schedule 13D is Panacea Innovation Limited, at 16.1%. No bankruptcy or receivership appears in its SEC Form 8-K filings. Passive holders reporting on Schedule 13G include EcoR1 Capital, LLC (17.4%), Adage Capital (8.56%), Point72 (7.6%) (Schedule 13D/A, May 11, 2026).
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Is Atara Biotherapeutics, Inc. a real, registered company?
- Atara Biotherapeutics, Inc. files with the SEC under CIK 1604464 (its SEC filings).
- Its shares are listed under the ticker ATRA on Nasdaq (SEC company record).
- Incorporated in Delaware; business address in Thousand Oaks, California, as its SEC filings state.
- Court and bankruptcy records: see Before you sign or pay below.
Before you sign or pay
- Court and bankruptcy: No federal court case or bankruptcy filing found under Atara Biotherapeutics, Inc. in our court records and SEC 8-K records (as of 2026-11-06).
- Layoffs: 1 exit or restructuring plan reported on Form 8-K, Item 2.05 (latest filed 2025-10-07, about 15 jobs).
- Leadership changes: the latest reported is Kevin G. Sarney (Form 8-K filed 2026-06-26). Check you are dealing with the people now in charge.
- Ownership: 5%+ holders are reported on Schedule 13D or 13G; the latest names Point72 (filed 2026-08-14).
Who are Atara Biotherapeutics, Inc.'s owners and officers?
Atara Biotherapeutics, Inc.: incorporated in Delaware; business address in Thousand Oaks, California; industry Biological Products, (No Diagnostic Substances) (Schedule 13G/A, 2026-08-14).
| Report | Holder | Share |
|---|---|---|
| Schedule 13G/A, 2026-08-14 | Point72 Asset Management, L.P. | 7.6% |
| Schedule 13D/A, 2026-07-24 | Redmile Group, LLC | 9.9% |
| Schedule 13D/A, 2026-05-14 | Redmile Group, LLC | 9.9% |
| Schedule 13G, 2026-05-13 | Adage Capital Management, L.P. | 8.56% |
| Schedule 13D/A, 2026-05-11 | Panacea Innovation Limited | 16.1% |
| Schedule 13G, 2026-05-08 | Point72 Asset Management, L.P. | 6.2% |
| Schedule 13G/A, 2026-05-07 | Ecor1 Capital, LLC | 17.4% |
| Schedule 13D/A, 2026-01-14 | Panacea Innovation Limited | 19.99% |
| Schedule 13D/A, 2025-11-14 | Redmile Group, LLC | 9.9% |
| Schedule 13G/A, 2025-11-14 | Ecor1 Capital, LLC | 9.9% |
| Schedule 13D/A, 2025-08-19 | Panacea Innovation Limited | 20% |
Questions about who owns Atara Biotherapeutics, Inc.
Who owns Atara Biotherapeutics, Inc.?
On this page, 5 holders' latest ownership filings report 5% or more of Atara Biotherapeutics, Inc.: Ecor1 Capital, LLC (17.4%, Schedule 13G/A, filed 2026-05-07), Panacea Innovation Limited (16.1%, Schedule 13D/A, filed 2026-05-11), Redmile Group, LLC (9.9%, Schedule 13D/A, filed 2026-07-24), Adage Capital Management, L.P. (8.56%, Schedule 13G, filed 2026-05-13) and Point72 Asset Management, L.P. (7.6%, Schedule 13G/A, filed 2026-08-14).
Who are the largest shareholders of Atara Biotherapeutics, Inc.?
By the share each holder's latest filing reports, the largest holders of Atara Biotherapeutics, Inc. on this page are Ecor1 Capital, LLC (17.4%), Panacea Innovation Limited (16.1%) and Redmile Group, LLC (9.9%).
When did Ecor1 Capital, LLC buy into Atara Biotherapeutics, Inc.?
The filings give report dates, not purchase dates. The earliest filing from Ecor1 Capital, LLC on this page is the Schedule 13G/A, filed 2025-11-14, reporting 9.9%; its latest, Schedule 13G/A filed 2026-05-07, reports 17.4%. That earliest filing is itself an amendment, which updates an earlier report.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 11 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
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| Filed | Person | Role | Change | Effective |
|---|---|---|---|---|
| Form 8-K, 2026-06-26 | Kevin G. Sarney | appointed | 2026-06-26 | |
| Form 8-K, 2026-06-12 | Brian Cherry | Director | appointed | 2026-06-11 |
Which insiders own Atara Biotherapeutics, Inc. shares?
Directors, officers and holders of 10% or more report their shares on Forms 3, 4 and 5. Each line is the latest such report, largest holding first.
- EcoR1 Capital, LLC, a 10% owner: 1,552,000 shares (15.5% of shares outstanding), held indirectly (the form names the holder only in its footnotes) (Form 4, 2026-05-11).
- , a director and 10% owner: 1,318,894 shares (13.1% of shares outstanding), held indirectly (the form names the holder only in its footnotes), on a joint filing (Form 4, 2026-05-11).
- Panacea Innovation Ltd, a 10% owner: 1,318,894 shares (13.1% of shares outstanding), held indirectly (the form names the holder only in its footnotes), on a joint filing (Form 4, 2026-05-11).
- , a director and 10% owner: 1,221,395 shares (12.2% of shares outstanding), 12,000 held directly and 1,209,395 indirectly (Form 4, 2026-06-11).
- Adiumentum Capital Fund I GP LLC, a director and 10% owner: 1,209,395 shares (12.0% of shares outstanding), on a joint filing (Form 4, 2025-05-16).
Shares outstanding: 10,037,710 as of 2026-08-10, from the company's latest SEC cover page.
How much has Atara Biotherapeutics, Inc. raised?
No fundraising or offering filing from Atara Biotherapeutics, Inc. is on file with us.
Red flags found
1 exit or restructuring plan on Form 8-K (latest Form 8-K, 2025-10-07).
Keep reading
More on Atara Biotherapeutics, Inc. and the records around it.
Atara Biotherapeutics, Inc. elsewhere on the record
- 5%+ stake filings Aug 2026
- Leadership changes Jun 2026
- Layoff notices Oct 2025
Companies that share a holder
- Panacea Innovation Limited also filed stake reports on 3 other companies: Connect Biopharma Holdings Limited (Apr 2026), CASI Pharmaceuticals, Inc. (Dec 2025), Adagene Inc. (Nov 2025)
- Redmile Group, LLC also filed stake reports on 18 other companies: FATE THERAPEUTICS INC (Nov 2026), Electra Therapeutics, Inc. (Sep 2026), Neurogene Inc. (Aug 2026)
- EcoR1 Capital, LLC also filed stake reports on 20 other companies: Mereo BioPharma Group plc (Aug 2026), Alto Neuroscience, Inc. (Jul 2026), Fulcrum Therapeutics, Inc. (Jun 2026)
Related pages
LayoffsLeadership changes5%+ holders
Filings, cases and notices link to their records. A not-found line names the records searched; it is not proof of absence.
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https://mentionfox.com/who-owns/atara-biotherapeutics