SEC Form 4 · Updated Daily
ATRA
— ATARA BIOTHERAPEUTICS, INC. OwnershipInsider and institutional ownership derived from SEC Form 4 filings. Click any owner to see their holdings across every company they’ve filed on, and how their position has changed over time.
Current Reporting Owners
| Owner | Role | Shares Owned | As Of | Last Activity |
|---|---|---|---|---|
| Domain Partners VIII, L.P. | 10%+ Owner | 2,141,542 | 2014-10-21 | P |
| KPCB XV Associates, LLC | 10%+ Owner | 2,113,528 | 2015-05-19 | J |
| Kleiner Perkins Caufield & Byers XV, LLC | 10%+ Owner | 2,113,528 | 2015-05-19 | J |
| KPCB XV Founders Fund, LLC | 10%+ Owner | 2,113,528 | 2015-05-19 | J |
| Williams Greg | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| DAG Ventures V, L.P. | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| Pianim Nicholas K. | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| Cadeddu John J. | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| DAG Ventures V-QP, L.P. | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| Goodrich R. Thomas | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| DAG Ventures Management V, LLC | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| Chung Young J. | 10%+ Owner | 1,902,798 | 2014-10-21 | C |
| EcoR1 Capital, LLC | 10%+ Owner | 1,552,000 | 2026-05-07 | P |
| Adiumentum Capital Fund I LP | 10%+ Owner · Director | 1,209,395 | 2025-05-16 | A |
| Adiumentum Capital Fund I GP LLC | 10%+ Owner · Director | 1,209,395 | 2025-05-16 | A |
| Panacea Innovation Ltd | 10%+ Owner | 1,011,000 | 2026-05-07 | S |
| Huang James | 10%+ Owner · Director | 1,011,000 | 2026-05-07 | S |
| MARCUS JOEL S | Director · Officer | 888,355 | 2019-03-15 | S |
| Green Jeremy | Director | 636,912 | 2026-07-22 | M |
| Redmile Group, LLC | Director | 636,912 | 2026-07-22 | M |
| DOBMEIER ERIC | Director | 563,325 | 2023-11-10 | P |
| Ciechanover Isaac E. | Director · Officer | 294,337 | 2019-05-29 | S |
| Dupont Jakob | Officer | 290,794 | 2023-03-02 | S |
| Banard Charlene A. | Officer | 276,010 | 2023-05-16 | S |
| Haqq Christopher | Officer | 271,943 | 2019-02-15 | S |
| Soffer Gad | Officer | 243,966 | 2018-09-22 | F |
| Koppikar Utpal | Director | 181,978 | 2023-03-02 | S |
| Yarema Kristin | Officer | 171,415 | 2022-03-01 | A |
| Joshi Manher | Officer | 171,284 | 2023-11-16 | S |
| Cherry Brian N | Director | 166,486 | 2026-09-04 | P |
| Nguyen AnhCo | Director · Officer | 132,775 | 2026-08-17 | S |
| SEIDENBERG BETH C | Director | 115,689 | 2023-05-31 | A |
| Newell Joe | Officer | 113,097 | 2021-11-16 | S |
| Clark Mitchall G. | Officer | 107,972 | 2018-05-18 | S |
| MCGRATH JOHN | Officer | 91,762 | 2018-03-19 | S |
| Berger Dietmar | Officer | 85,678 | 2019-05-07 | F |
| Touchon Pascal | Director | 77,955 | 2025-06-10 | A |
| Turner Heather D | Officer | 77,112 | 2018-02-09 | S |
| Kim Mina | Officer | 66,389 | 2019-04-09 | F |
| Hyllengren Eric J | Officer | 56,231 | 2025-03-03 | S |
| Grant-Huerta Yanina | Officer | 49,636 | 2026-05-18 | S |
| Baynes Roy D. | Director | 43,500 | 2022-06-23 | A |
| HEIDEN WILLIAM K | Director | 34,188 | 2026-06-09 | A |
| Gallagher Carol Giltner | Director | 33,012 | 2025-06-10 | A |
| Porter Derrell | Officer | 31,688 | 2019-03-26 | A |
| Renaud Ronald C JR | Director | 31,500 | 2022-06-23 | A |
| Fust Matthew K | Director | 30,188 | 2026-06-09 | A |
| Murugan Amar | Officer | 27,108 | 2024-08-16 | S |
| Henrich Jill | Officer | 18,679 | 2025-03-03 | S |
| Roncarolo Maria Grazia | Director | 17,368 | 2025-06-10 | A |
| MALLIK AMEET | Director | 16,928 | 2025-06-10 | A |
| TREU JESSE I | Director | 15,890 | 2014-10-21 | P |
| Halak Brian K | 10%+ Owner | 15,890 | 2014-10-21 | P |
| DOVEY BRIAN H | 10%+ Owner | 15,890 | 2014-10-21 | P |
| VITULLO NICOLE | 10%+ Owner | 15,890 | 2014-10-21 | P |
| DP VIII Associates, L.P. | 10%+ Owner | 15,890 | 2014-10-21 | P |
| BLAIR JAMES C | 10%+ Owner | 15,890 | 2014-10-21 | P |
| SCHOEMAKER KATHLEEN K | 10%+ Owner | 15,890 | 2014-10-21 | P |
| Ciongoli Gregory Austin | 10%+ Owner · Director | 12,000 | 2026-06-09 | A |
Recent Filings
| Date | Owner | Activity | Shares | Price | Owned After |
|---|---|---|---|---|---|
| 2026-09-04 | Cherry Brian N | Open-market buy | 104,166 | $9.60 | 166,486 |
| 2026-08-17 | Nguyen AnhCo | Open-market sale | 5,062 | $8.08 | 132,775 |
| 2026-07-22 | Green Jeremy | Option exercise (derivative) | 101,089 | $0.00 | 0 |
| 2026-07-22 | Green Jeremy | Tax withholding | 60 | — | 636,852 |
| 2026-07-22 | Green Jeremy | Option exercise | 195,211 | — | 636,912 |
| 2026-07-22 | Redmile Group, LLC | Option exercise (derivative) | 101,089 | $0.00 | 0 |
| 2026-07-22 | Redmile Group, LLC | Tax withholding | 60 | — | 636,852 |
| 2026-07-22 | Redmile Group, LLC | Option exercise | 195,211 | — | 636,912 |
| 2026-06-11 | Cherry Brian N | — | — | — | 38,320 |
| 2026-06-11 | Cherry Brian N | Grant / award | 24,000 | $0.00 | 62,320 |
| 2026-06-09 | Ciongoli Gregory Austin | Grant / award | 12,000 | $0.00 | 12,000 |
| 2026-06-09 | Fust Matthew K | Grant / award | 12,000 | $0.00 | 30,188 |
| 2026-06-09 | HEIDEN WILLIAM K | Grant / award | 12,000 | $0.00 | 34,188 |
| 2026-05-18 | Grant-Huerta Yanina | Open-market sale | 2,414 | $9.13 | 49,636 |
| 2026-05-18 | Nguyen AnhCo | Open-market sale | 5,241 | $9.13 | 137,837 |
| 2026-05-07 | EcoR1 Capital, LLC | — | — | — | 1,044,593 |
| 2026-05-07 | EcoR1 Capital, LLC | Open-market buy | 507,407 | $9.35 | 1,552,000 |
| 2026-05-07 | Huang James | Open-market sale | 313,446 | $10.10 | 1,011,000 |
| 2026-05-07 | Panacea Innovation Ltd | Open-market sale | 313,446 | $10.10 | 1,011,000 |
| 2026-03-17 | Huang James | Option exercise (derivative) | 259,163 | $6.61 | 0 |
| 2026-03-17 | Huang James | Tax withholding | 5 | $5.23 | 307,894 |
| 2026-03-17 | Huang James | Option exercise | 259,163 | $0.00 | 307,899 |
| 2026-03-17 | Panacea Innovation Ltd | Option exercise (derivative) | 259,163 | $6.61 | 0 |
| 2026-03-17 | Panacea Innovation Ltd | Tax withholding | 5 | $5.23 | 307,894 |
| 2026-03-17 | Panacea Innovation Ltd | Option exercise | 259,163 | $0.00 | 307,899 |
| 2026-03-09 | Grant-Huerta Yanina | Grant / award | 20,300 | $0.00 | 52,050 |
| 2026-03-09 | Nguyen AnhCo | Grant / award | 81,100 | $0.00 | 143,078 |
| 2026-03-02 | Nguyen AnhCo | Open-market sale | 1,442 | $5.09 | 61,978 |
| 2026-03-02 | Nguyen AnhCo | Open-market sale | 1,298 | $5.09 | 63,420 |
| 2026-03-02 | Nguyen AnhCo | Open-market sale | 58 | $5.08 | 64,718 |
| 2026-03-02 | Nguyen AnhCo | Open-market sale | 198 | $5.08 | 64,776 |
| 2026-03-02 | Grant-Huerta Yanina | Open-market sale | 100 | $5.08 | 31,750 |
| 2026-03-02 | Grant-Huerta Yanina | Open-market sale | 377 | $5.08 | 31,850 |
| 2026-03-02 | Grant-Huerta Yanina | Open-market sale | 1,603 | $5.08 | 32,227 |
| 2026-03-02 | Grant-Huerta Yanina | Open-market sale | 24 | $5.08 | 33,830 |
| 2026-01-12 | Huang James | Open-market sale | 80,554 | $6.07 | 1,324,446 |
| 2026-01-12 | Panacea Innovation Ltd | Open-market sale | 80,554 | $6.07 | 1,324,446 |
| 2025-11-28 | Huang James | Option exercise (derivative) | 48,737 | $6.61 | 259,163 |
| 2025-11-28 | Huang James | Tax withholding | 1 | $14.03 | 48,736 |
| 2025-11-28 | Huang James | Option exercise | 48,737 | $0.00 | 48,737 |
Source: SEC EDGAR Form 4 filings. For informational purposes only — not investment advice.