# Atara Biotherapeutics, Inc.: filings

ATRA · Nasdaq · CIK 1604464 · [Healthcare](/sectors/healthcare.md) · fiscal year ends Dec 31

Pages: [Overview](/companies/atra.md) · [Financials](/companies/atra/financials.md) · [Filings](/companies/atra/filings.md) · [Insiders](/companies/atra/insiders.md)

## Reports and events: 227 filings

Newest first, by EDGAR acceptance time (Eastern). Filter with ?form= one of: `periodic`, `8-K`, `10-K`, `10-Q`, `4`, `proxy`, `13dg`, `all`, or any form this company filed (4 595, 8-K 146, SC 13G/A 68, 3 43, 10-Q 36, 144 36, SC 13G 23, 424B5 19, S-8 19, DEFA14A 14, 10-K 12, CORRESP 12, DEF 14A 12, UPLOAD 9, EFFECT 7, SCHEDULE 13D/A 7, 4/A 6, CT ORDER 6, S-1/A 6, SCHEDULE 13G/A 4, S-1 3, S-3 3, SCHEDULE 13G 3, 424B3 2, 424B4 2, DRS/A 2, DRSLTR 2, PRE 14A 2, S-1MEF 2, S-3ASR 2, SCHEDULE 13D 2, 10-K/A 1, 424B1 1, 8-A12B 1, CERTNAS 1, DEFR14A 1, DEL AM 1, DRS 1, FWP 1, POS AM 1, POSASR 1, SC 13D 1, SC 13D/A 1).

| Filed | Accepted | Form | What it is | Accession |
| --- | --- | --- | --- | --- |
| 2026-08-12 | 16:15 ET | [10-Q](/filings/0001193125-26-346885.md) | Quarterly report, period 2026-06-30 | 0001193125-26-346885 |
| 2026-08-12 | 16:10 ET | [8-K](/filings/0001193125-26-346857.md) | 2.02 Results of operations | 0001193125-26-346857 |
| 2026-07-24 | 20:00 ET | [SCHEDULE 13D/A](/filings/0001104659-26-086728.md) | Ownership report, active investor, amended | 0001104659-26-086728 |
| 2026-06-26 | 16:15 ET | [8-K](/filings/0001193125-26-285498.md) | 5.02 Departure or appointment of officers or directors | 0001193125-26-285498 |
| 2026-06-12 | 16:05 ET | [8-K](/filings/0001213900-26-068264.md) | 5.02 Departure or appointment of officers or directors; 5.07 Shareholder vote results | 0001213900-26-068264 |
| 2026-05-14 | 21:00 ET | [SCHEDULE 13D/A](/filings/0001104659-26-061506.md) | Ownership report, active investor, amended | 0001104659-26-061506 |
| 2026-05-12 | 16:15 ET | [10-Q](/filings/0001193125-26-219482.md) | Quarterly report, period 2026-03-31 | 0001193125-26-219482 |
| 2026-05-12 | 16:10 ET | [8-K](/filings/0001193125-26-219420.md) | 9.01 Financial statements and exhibits | 0001193125-26-219420 |
| 2026-05-11 | 18:49 ET | [SCHEDULE 13D/A](/filings/0001193125-26-217389.md) | Ownership report, active investor, amended | 0001193125-26-217389 |
| 2026-05-07 | 08:10 ET | [8-K](/filings/0001193125-26-210413.md) | 8.01 Other events | 0001193125-26-210413 |
| 2026-05-01 | 16:05 ET | [8-K](/filings/0001193125-26-201397.md) | 3.01 Delisting notice | 0001193125-26-201397 |
| 2026-04-24 | 16:15 ET | [DEF 14A](/filings/0001193125-26-177285.md) | Proxy statement, period 2026-04-24 | 0001193125-26-177285 |
| 2026-03-16 | 16:15 ET | [10-K](/filings/0001193125-26-108361.md) | Annual report, period 2025-12-31 | 0001193125-26-108361 |
| 2026-03-16 | 16:10 ET | [8-K](/filings/0001193125-26-108344.md) | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0001193125-26-108344 |
| 2026-03-12 | 08:10 ET | [8-K](/filings/0001193125-26-103127.md) | 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-26-103127 |
| 2026-03-03 | 08:30 ET | [8-K](/filings/0001193125-26-086793.md) | 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-26-086793 |
| 2026-02-23 | 08:29 ET | [8-K](/filings/0001193125-26-062534.md) | 1.01 Entry into a material agreement; 3.02 Unregistered sale of equity; 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-26-062534 |
| 2026-01-14 | 21:20 ET | [SCHEDULE 13D/A](/filings/0001193125-26-013362.md) | Ownership report, active investor, amended | 0001193125-26-013362 |
| 2026-01-12 | 16:00 ET | [8-K](/filings/0001193125-26-010342.md) | 2.02 Results of operations; 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-26-010342 |
| 2026-01-02 | 16:01 ET | [8-K](/filings/0001193125-26-000907.md) | 1.01 Entry into a material agreement; 9.01 Financial statements and exhibits | 0001193125-26-000907 |
| 2025-11-14 | 16:19 ET | [SCHEDULE 13D/A](/filings/0001104659-25-112574.md) | Ownership report, active investor, amended | 0001104659-25-112574 |
| 2025-11-12 | 09:10 ET | [10-Q](/filings/0001193125-25-276219.md) | Quarterly report, period 2025-09-30 | 0001193125-25-276219 |
| 2025-11-12 | 09:05 ET | [8-K](/filings/0001193125-25-276209.md) | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0001193125-25-276209 |
| 2025-10-07 | 17:32 ET | [8-K](/filings/0001193125-25-232117.md) | 2.05 Exit or disposal costs | 0001193125-25-232117 |
| 2025-09-04 | 18:05 ET | [8-K](/filings/0000950170-25-112898.md) | 5.02 Departure or appointment of officers or directors | 0000950170-25-112898 |
| 2025-08-19 | 20:15 ET | [SCHEDULE 13D/A](/filings/0000950170-25-110311.md) | Ownership report, active investor, amended | 0000950170-25-110311 |
| 2025-08-11 | 16:10 ET | [10-Q](/filings/0000950170-25-106550.md) | Quarterly report, period 2025-06-30 | 0000950170-25-106550 |
| 2025-08-11 | 16:05 ET | [8-K](/filings/0000950170-25-106533.md) | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-25-106533 |
| 2025-07-14 | 16:03 ET | [8-K](/filings/0001193125-25-158719.md) | 2.02 Results of operations; 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-25-158719 |
| 2025-06-11 | 16:15 ET | [8-K](/filings/0001193125-25-139150.md) | 5.07 Shareholder vote results | 0001193125-25-139150 |
| 2025-05-23 | 16:05 ET | [SCHEDULE 13D](/filings/0001104659-25-052422.md) | Ownership report, active investor | 0001104659-25-052422 |
| 2025-05-21 | 18:00 ET | [SCHEDULE 13D](/filings/0000950170-25-075903.md) | Ownership report, active investor | 0000950170-25-075903 |
| 2025-05-16 | 18:28 ET | [SCHEDULE 13D/A](/filings/0001104659-25-050119.md) | Ownership report, active investor, amended | 0001104659-25-050119 |
| 2025-05-16 | 17:26 ET | [8-K](/filings/0001193125-25-121824.md) | 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-25-121824 |
| 2025-05-15 | 08:45 ET | [10-Q](/filings/0000950170-25-072040.md) | Quarterly report, period 2025-03-31 | 0000950170-25-072040 |
| 2025-05-15 | 08:41 ET | [8-K](/filings/0001193125-25-120345.md) | 2.02 Results of operations; 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0001193125-25-120345 |
| 2025-05-12 | 16:10 ET | [8-K](/filings/0000950170-25-069198.md) | 2.05 Exit or disposal costs | 0000950170-25-069198 |
| 2025-05-06 | 16:05 ET | [8-K](/filings/0001193125-25-113811.md) | 8.01 Other events; 9.01 Financial statements and exhibits | 0001193125-25-113811 |
| 2025-04-28 | 16:15 ET | [DEF 14A](/filings/0000950170-25-059322.md) | Proxy statement, period 2025-06-10 | 0000950170-25-059322 |
| 2025-04-04 | 16:10 ET | [8-K](/filings/0000950170-25-051121.md) | 1.01 Entry into a material agreement | 0000950170-25-051121 |
| 2025-03-31 | 16:28 ET | [8-K](/filings/0001193125-25-068789.md) | 5.02 Departure or appointment of officers or directors | 0001193125-25-068789 |
| 2025-03-07 | 16:10 ET | [10-K](/filings/0000950170-25-035507.md) | Annual report, period 2024-12-31 | 0000950170-25-035507 |
| 2025-03-07 | 16:05 ET | [8-K](/filings/0000950170-25-035482.md) | 2.02 Results of operations; 9.01 Financial statements and exhibits | 0000950170-25-035482 |
| 2025-03-03 | 16:05 ET | [8-K](/filings/0000950170-25-030832.md) | 2.05 Exit or disposal costs; 9.01 Financial statements and exhibits | 0000950170-25-030832 |
| 2025-01-27 | 16:30 ET | [8-K](/filings/0000950170-25-009225.md) | 2.05 Exit or disposal costs; 9.01 Financial statements and exhibits | 0000950170-25-009225 |
| 2025-01-21 | 07:36 ET | [8-K](/filings/0000950170-25-006992.md) | 8.01 Other events; 9.01 Financial statements and exhibits | 0000950170-25-006992 |
| 2025-01-16 | 16:05 ET | [8-K](/filings/0000950170-25-006191.md) | 2.02 Results of operations; 8.01 Other events; 9.01 Financial statements and exhibits | 0000950170-25-006191 |
| 2024-12-23 | 16:00 ET | [8-K](/filings/0001193125-24-284167.md) | 5.03 Amendment to articles or bylaws; 9.01 Financial statements and exhibits | 0001193125-24-284167 |
| 2024-11-12 | 16:10 ET | [10-Q](/filings/0000950170-24-125389.md) | Quarterly report, period 2024-09-30 | 0000950170-24-125389 |
| 2024-11-12 | 16:05 ET | [8-K](/filings/0000950170-24-125334.md) | 2.02 Results of operations; 5.02 Departure or appointment of officers or directors; 9.01 Financial statements and exhibits | 0000950170-24-125334 |

Page 1 of 5. [Older](/companies/atra/filings.md?page=2)
Source: SEC EDGAR, the company’s filing index. Last ingested by Listed: Oct 24, 2026, 15:14 ET. No prices; not investment advice.