Atara Biotherapeutics, Inc. (ATRA) has 20 known insider and institutional holders on record. The largest holder is Panacea Innovation Ltd with 1,324,446 shares. Other notable holders include MARCUS JOEL S and DOBMEIER ERIC.
Over the last 12 months, insiders have made 25 transactions in ATRA stock — 11 buys (valued at $856.82K) and 9 sells (valued at $573.93K). Insider buying has outpaced selling during this period, which may signal confidence in the company's prospects.
ATRA Insider Ownership
Top Holder
Panacea Innovation Ltd
1,324,446 shares
Buys (12 mo)
11
$856.82K value
Sells (12 mo)
9
$573.93K value
12-Month Transaction Activity
Top Insider Holders
| # |
Name |
Role |
Shares Owned |
Last Filed |
Relative Size |
| 1 |
Panacea Innovation Ltd |
10 Percent Owner |
1,324,446 |
2026-01-14 |
|
| 2 |
Marcus Joel S |
Director |
888,355 |
2019-03-19 |
|
| 3 |
Dobmeier Eric |
Director |
563,325 |
2023-11-14 |
|
| 4 |
Adiumentum Capital Fund I Lp |
10 Percent Owner, Other: See Remarks |
377,193 |
2025-05-16 |
|
| 5 |
Ciechanover Isaac E. |
Chief Executive Officer |
293,612 |
2019-05-31 |
|
| 6 |
Dupont Jakob |
EVP, Head of R&d |
290,794 |
2023-03-06 |
|
| 7 |
Banard Charlene A. |
EVP, Chief Technical Officer |
276,010 |
2023-05-18 |
|
| 8 |
Haqq Christopher |
EVP, R&d & Chief Scientific Of |
271,943 |
2019-02-19 |
|
| 9 |
Soffer Gad |
EVP & Chief Strategy Officer |
243,966 |
2018-09-25 |
|
| 10 |
Koppikar Utpal |
Chief Financial Officer |
181,978 |
2023-03-06 |
|
| 11 |
Joshi Manher |
EVP, Chief Medical Officer |
171,284 |
2023-11-20 |
|
| 12 |
Nguyen Anhco |
President and CEO |
143,078 |
2026-03-11 |
|
| 13 |
Newell Joe |
Chief Operations Officer |
113,097 |
2021-11-18 |
|
| 14 |
Clark Mitchall G. |
EVP & Chief R & Qa Officer |
107,972 |
2018-05-21 |
|
| 15 |
Mcgrath John |
EVP & Chief Financial Officer |
91,762 |
2018-03-20 |
|
| 16 |
Berger Dietmar |
Global Head of R&d |
85,678 |
2019-05-08 |
|
| 17 |
Yarema Kristin |
Chief Commercial Officer |
85,592 |
2022-03-03 |
|
| 18 |
Seidenberg Beth C |
Director |
79,500 |
2023-06-02 |
|
| 19 |
Touchon Pascal |
Director |
77,955 |
2025-06-12 |
|
| 20 |
Turner Heather D |
Former EVP, Gc & Sec. |
69,494 |
2018-02-12 |
|
Recent Transactions (last 12 months)
| Date |
Name |
Role |
Type |
Shares |
Price |
Value |
| 2026-03-17 |
Panacea Innovation Ltd |
10 Percent Owner |
Option Exercise (Sell) |
259,163 |
$0.00 |
$25.92 |
| 2026-03-09 |
Grant-huerta Yanina |
Chief Accounting Officer |
RSU Award |
20,300 |
- |
- |
| 2026-03-09 |
Nguyen Anhco |
President and CEO |
RSU Award |
81,100 |
- |
- |
| 2026-03-02 |
Grant-huerta Yanina |
Chief Accounting Officer |
Informative Sell |
100 |
$5.08 |
$508.30 |
| 2026-03-02 |
Nguyen Anhco |
President and CEO |
Informative Sell |
1,442 |
$5.09 |
$7.34K |
| 2026-01-12 |
Panacea Innovation Ltd |
10 Percent Owner |
Informative Sell |
80,554 |
$6.07 |
$489.02K |
| 2025-11-28 |
Panacea Innovation Ltd |
10 Percent Owner |
Tax Withholding of RSU |
1 |
$14.03 |
$14.03 |
| 2025-11-17 |
Grant-huerta Yanina |
Chief Accounting Officer |
Informative Sell |
74 |
$13.19 |
$976.13 |
| 2025-11-17 |
Nguyen Anhco |
President and CEO |
Informative Sell |
56 |
$13.19 |
$738.53 |
| 2025-08-18 |
Grant-huerta Yanina |
Chief Accounting Officer |
Informative Sell |
1,668 |
$11.61 |
$19.37K |
| 2025-08-18 |
Nguyen Anhco |
President and CEO |
Informative Sell |
1,620 |
$11.62 |
$18.82K |
| 2025-08-15 |
Panacea Innovation Ltd |
10 Percent Owner |
Informative Buy |
55,000 |
$12.19 |
$670.42K |
| 2025-07-17 |
Panacea Innovation Ltd |
10 Percent Owner |
Informative Buy |
19,335 |
$9.64 |
$186.37K |
| 2025-06-10 |
Mallik Ameet |
Director |
RSU Award |
7,828 |
- |
- |
| 2025-06-10 |
Roncarolo Maria Grazia |
Director |
RSU Award |
7,828 |
- |
- |
| 2025-06-10 |
Touchon Pascal |
Director |
RSU Award |
7,828 |
- |
- |
| 2025-06-10 |
Fust Matthew K |
Director |
RSU Award |
7,828 |
- |
- |
| 2025-06-10 |
Gallagher Carol Giltner |
Director |
RSU Award |
7,828 |
- |
- |
| 2025-06-10 |
Heiden William K |
Director |
RSU Award |
7,828 |
- |
- |
| 2025-05-16 |
Subramanian Nachiappan |
Director |
Unknown |
- |
- |
- |
| 2025-05-16 |
Redmile Group, Llc |
Director |
Unknown |
4,872 |
$9.32 |
$45.38K |
| 2025-05-16 |
Panacea Innovation Ltd |
10 Percent Owner |
Unknown |
307,900 |
$0.00 |
$30.79 |
| 2025-05-16 |
Grant-huerta Yanina |
Chief Accounting Officer |
Informative Sell |
2,218 |
$6.76 |
$15K |
| 2025-05-16 |
Nguyen Anhco |
President and CEO |
Informative Sell |
3,276 |
$6.76 |
$22.16K |
| 2025-05-16 |
Adiumentum Capital Fund I Lp |
10 Percent Owner, Other: See Remarks |
RSU Award |
227,000 |
$0.00 |
$22.70 |
