ATRA
Atara Biotherapeutics, Inc. · Healthcare · Market cap $102.7M
Insiders bought $959K net in the last 90 days ·1 seller, 1 buyer· latest Form 4 filed Sep 4, 2026
Insider Buying
$5.7M
reported purchases (SEC code P)
Insider Selling
$3.9M
reported sales (SEC code S)
Unique Insiders
5
in the rolling window
Latest filing
Sep 4, 2026
Cherry Brian N
Atara Biotherapeutics, Inc. (ATRA) has 20 SEC Form 4 filings (32 transaction rows) in the rolling window, disclosed by 5 distinct insiders. Most recent filing: Sep 4, 2026.
Inside the rolling window, 5 insiders at Atara Biotherapeutics, Inc. reported 2 open-market purchases totaling $5.7M and 9 open-market sales totaling $3.9M. The most active filer is President and CEO Nguyen AnhCo with 4 filings. Insiders have net bought $2.5M over the trailing 6 months. The largest single insider purchase in this window was $4.7M by 10% Owner EcoR1 Capital, LLC on May 7, 2026. The most recent open-market filing is a purchase of 104,166 shares by Director Cherry Brian N, dated Sep 4, 2026, worth $1000K.
- Industry:Biotechnology
- CEO:Anhco Nguyen
- Employees:10
- HQ:Thousand Oaks, CA, US
- IPO:2014-10-16
| Source | |||||||
|---|---|---|---|---|---|---|---|
Cherry Brian NFirst filing | Director | Purchase | 104,166 | $1000K | Sep 4 | +4.8% | SEC ↗ |
Nguyen AnhCoFirst in 3 months | President and CEO | Sale | 5,062 | $41K | Aug 26 | +9.1% | SEC ↗ |
| Chief Accounting Officer | Sale | 2,414 | $22K | May 20 | +8.3% | SEC ↗ | |
| President and CEO | Sale | 5,241 | $48K | May 20 | +8.3% | SEC ↗ | |
Panacea Innovation LtdFirst in 4 months | 10% Owner | Sale | 313,446 | $3.2M | May 11 | +16.5% | SEC ↗ |
| 10% Owner | Purchase | 507,407 | $4.7M | May 11 | +16.5% | SEC ↗ | |
Grant-Huerta YaninaFirst in 4 months | Chief Accounting Officer | Sale | 2,104 | $11K | Mar 4 | +89.8% | SEC ↗ |
Nguyen AnhCoFirst in 4 months | President and CEO | Sale | 2,996 | $15K | Mar 4 | — | SEC ↗ |
Panacea Innovation LtdFirst filing | 10% Owner | Sale | 80,554 | $489K | Jan 14 | — | SEC ↗ |
Grant-Huerta YaninaFirst filing | Chief Accounting Officer | Sale | 1,804 | $24K | Nov 19 | — | SEC ↗ |
Nguyen AnhCoFirst filing | President and CEO | Sale | 2,915 | $38K | Nov 19 | — | SEC ↗ |
Frequently asked questions
How many SEC Form 4 insider filings does ATRA have?
Atara Biotherapeutics, Inc. (ATRA) has 20 SEC Form 4 filings (32 transaction rows) in the rolling 365-day window, disclosed by 5 distinct insiders. Most recent filing: Sep 4, 2026.
When was the most recent SEC Form 4 filing for ATRA?
The most recent Form 4 filing for ATRA on Tracefour is dated Sep 4, 2026.
Who is the most active insider at ATRA?
The most active SEC Form 4 filer at ATRA in the rolling window is President and CEO Nguyen AnhCo, with 4 filings.
What is the net insider flow at ATRA over the last 6 months?
Over the trailing 180 days, insiders at ATRA have net bought $2.5M based on SEC Form 4 disclosures.
What was the largest insider purchase at ATRA?
The largest single insider open-market purchase at ATRA in the rolling window was $4.7M by 10% Owner EcoR1 Capital, LLC on 2026-05-07.
What is the total insider buy and sell value at ATRA in the current window?
Inside the rolling window, insiders at ATRA bought $5.7M and sold $3.9M based on SEC Form 4 filings.
Can I get alerts for ATRA insider trading?
Yes. Tracefour sends a free email when a new SEC Form 4 purchase or sale is filed at Atara Biotherapeutics, Inc. (ATRA). Alerts are set per company from the page itself, there is no paid tier, and each email links to the original filing on SEC EDGAR.
Related companies
Atara Biotherapeutics, Inc. is in the Healthcare sector.