Atara Biotherapeutics SEC Filings
NASDAQ: ATRAHealth CareBiotechnology: Biological Products (No Diagnostic Substances)USD
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At close: Oct 9, 4:00 PM ET · Delayed 15 min
Atara Biotherapeutics filing overview
This page lists 60 recent SEC filings by Atara Biotherapeutics (ATRA), including 24 4, 16 8-K, 6 SCHEDULE 13D/A, 4 10-Q. The latest annual report (10-K) was filed on Mar 16, 2026 for the period ending Dec 31, 2025. The most recent quarterly report (10-Q) was filed on Aug 12, 2026.
The latest current report (8-K), used to disclose material events such as earnings releases and executive changes, was filed on Aug 12, 2026. Form 10-K is the audited annual report, 10-Q the quarterly report, 8-K covers material events, and Form 4 reports insider transactions. All documents link directly to SEC EDGAR.
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ATRA SEC filings
| Filed | Form | Description | Document |
|---|---|---|---|
| Sep 4, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Aug 26, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Aug 14, 2026 | SCHEDULE 13G/A | Beneficial ownership report (passive) (amendment) | View on EDGAR |
| Aug 12, 2026 | 8-K | Results of Operations and Financial Condition | View on EDGAR |
| Aug 12, 2026 | 10-Q | Quarterly report | View on EDGAR |
| Jul 24, 2026 | SCHEDULE 13D/A | Beneficial ownership report (activist) (amendment) | View on EDGAR |
| Jul 24, 2026 | 4 | OWNERSHIP DOCUMENT | View on EDGAR |
| Jun 26, 2026 | 8-K | Departure or Appointment of Directors or Officers; Compensatory Arrangements | View on EDGAR |
| Jun 15, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Jun 12, 2026 | 8-K | Departure or Appointment of Directors or Officers; Compensatory Arrangements; Submission of Matters to a Vote of Security Holders | View on EDGAR |
| Jun 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Jun 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Jun 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| May 20, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| May 20, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| May 14, 2026 | SCHEDULE 13D/A | Beneficial ownership report (activist) (amendment) | View on EDGAR |
| May 13, 2026 | SCHEDULE 13G | Beneficial ownership report (passive) | View on EDGAR |
| May 12, 2026 | 8-K | Current report | View on EDGAR |
| May 12, 2026 | 10-Q | Quarterly report | View on EDGAR |
| May 12, 2026 | 424B5 | Prospectus | View on EDGAR |
| May 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| May 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| May 11, 2026 | SCHEDULE 13D/A | Beneficial ownership report (activist) (amendment) | View on EDGAR |
| May 8, 2026 | SCHEDULE 13G | Beneficial ownership report (passive) | View on EDGAR |
| May 7, 2026 | SCHEDULE 13G/A | Beneficial ownership report (passive) (amendment) | View on EDGAR |
| May 7, 2026 | 8-K | Other Events | View on EDGAR |
| May 1, 2026 | 8-K | Notice of Delisting or Failure to Satisfy a Continued Listing Rule; Transfer of Listing | View on EDGAR |
| Apr 24, 2026 | DEF 14A | Definitive proxy statement | View on EDGAR |
| Mar 25, 2026 | 424B3 | Prospectus | View on EDGAR |
| Mar 19, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Mar 16, 2026 | 8-K | Results of Operations and Financial Condition | View on EDGAR |
| Mar 16, 2026 | 10-K | Annual report | View on EDGAR |
| Mar 16, 2026 | 424B5 | Prospectus | View on EDGAR |
| Mar 12, 2026 | 8-K | Other Events | View on EDGAR |
| Mar 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Mar 11, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Mar 4, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Mar 4, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Mar 3, 2026 | 8-K | Other Events | View on EDGAR |
| Feb 23, 2026 | 8-K | Entry into a Material Definitive Agreement; Unregistered Sales of Equity Securities; Other Events | View on EDGAR |
| Jan 14, 2026 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Jan 14, 2026 | SCHEDULE 13D/A | Beneficial ownership report (activist) (amendment) | View on EDGAR |
| Jan 12, 2026 | 8-K | Results of Operations and Financial Condition; Other Events | View on EDGAR |
| Jan 2, 2026 | 8-K | Entry into a Material Definitive Agreement | View on EDGAR |
| Dec 1, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Nov 19, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Nov 19, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Nov 14, 2025 | SCHEDULE 13G/A | Beneficial ownership report (passive) (amendment) | View on EDGAR |
| Nov 14, 2025 | SCHEDULE 13D/A | Beneficial ownership report (activist) (amendment) | View on EDGAR |
| Nov 12, 2025 | 8-K | Results of Operations and Financial Condition | View on EDGAR |
| Nov 12, 2025 | 10-Q | Quarterly report | View on EDGAR |
| Oct 7, 2025 | 8-K | Costs Associated with Exit or Disposal Activities | View on EDGAR |
| Sep 4, 2025 | 8-K | Departure or Appointment of Directors or Officers; Compensatory Arrangements | View on EDGAR |
| Aug 20, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Aug 20, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Aug 19, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |
| Aug 19, 2025 | SCHEDULE 13D/A | Beneficial ownership report (activist) (amendment) | View on EDGAR |
| Aug 11, 2025 | 8-K | Results of Operations and Financial Condition | View on EDGAR |
| Aug 11, 2025 | 10-Q | Quarterly report | View on EDGAR |
| Jul 21, 2025 | 4 | Statement of changes in beneficial ownership | View on EDGAR |