Atara Biotherapeutics, Inc. Insider Trading Activity
Every SEC Form 4 insider transaction reported for Atara Biotherapeutics, Inc. (ATRA), sourced directly from SEC EDGAR and updated as new filings are accepted.
By Trabud · Insider-trading data from SEC EDGAR
Latest filing:
Compiled automatically from SEC EDGAR Form 4 filings and refreshed daily. Figures count purchases (code P) and sales (code S) only — not grants, option exercises, or gifts. How this page is built. Not investment advice.
Quick Answer
Are ATRA insiders buying or selling?
In the last 12 months, Atara Biotherapeutics, Inc. insiders reported 2 open-market purchases ($5.7M) and 9 sales ($3.9M) — net buying of $1.9M. Since January 2018, Trabud has recorded 222 Form 4 filings for ATRA: 11 buys ($7.5M) and 211 sells ($47.6M).
Source: SEC EDGAR Form 4
What stands out
- The largest open-market purchase in the last 12 months was $4.7M by EcoR1 Capital, LLC (10% Owner) on May 11, 2026. SEC ↗
- The most recent open-market purchase was reported on Sep 4, 2026 (44 days ago).
Key Statistics (January 2018 – Sep 4, 2026)
Total Form 4 filings
222
SEC EDGAR
Insider filers
26
Insider buys (11)
$7.5M
Insider sells (211)
$47.6M
Insider sentiment
Net sellingNet insider flow of $40.1M in net selling since January 2018, and $1.9M in net buying over the last 12 months. 1 insider buy in the last 90 days.
Recent ATRA insider transactions
| Date | Insider | Role | Type | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| Sep 4, 2026 | Brian N Cherry | Director | Purchase | 104.2K | $9.60 | $1000.0K | SEC ↗ |
| Aug 26, 2026 | Anhco Nguyen | President and CEO | Sale | 5.1K | $8.08 | $40.9K | SEC ↗ |
| May 20, 2026 | Anhco Nguyen | President and CEO | Sale | 5.2K | $9.13 | $47.8K | SEC ↗ |
| May 20, 2026 | Yanina Grant-Huerta | Chief Accounting Officer | Sale | 2.4K | $9.13 | $22.0K | SEC ↗ |
| May 11, 2026 | Panacea Innovation Ltd | 10% Owner | Sale | 313.4K | $10.10 | $3.2M | SEC ↗ |
| May 11, 2026 | EcoR1 Capital, LLC | 10% Owner | Purchase | 507.4K | $9.35 | $4.7M | SEC ↗ |
| Mar 4, 2026 | Yanina Grant-Huerta | Chief Accounting Officer | Sale | 2.1K | $5.08 | $10.7K | SEC ↗ |
| Mar 4, 2026 | Anhco Nguyen | President and CEO | Sale | 3.0K | $5.09 | $15.2K | SEC ↗ |
| Jan 15, 2026 | Panacea Innovation Ltd | 10% Owner | Sale | 80.6K | $6.07 | $489.0K | SEC ↗ |
| Nov 19, 2025 | Anhco Nguyen | President and CEO | Sale | 2.9K | $13.19 | $38.4K | SEC ↗ |
| Nov 19, 2025 | Yanina Grant-Huerta | Chief Accounting Officer | Sale | 1.8K | $13.19 | $23.8K | SEC ↗ |
| Aug 20, 2025 | Panacea Innovation Ltd | 10% Owner | Purchase | 55.0K | $12.19 | $670.4K | SEC ↗ |
| Jul 21, 2025 | Panacea Innovation Ltd | 10% Owner | Purchase | 19.3K | $9.64 | $186.4K | SEC ↗ |
| May 20, 2025 | Yanina Grant-Huerta | Chief Accounting Officer | Sale | 2.2K | $6.76 | $15.0K | SEC ↗ |
| May 20, 2025 | Anhco Nguyen | President and CEO | Sale | 3.3K | $6.76 | $22.2K | SEC ↗ |
| Mar 5, 2025 | Anhco Nguyen | President and CEO | Sale | 3.3K | $7.00 | $23.3K | SEC ↗ |
| Mar 5, 2025 | Eric J Hyllengren | EVP, CFO and COO | Sale | 1.2K | $7.00 | $8.5K | SEC ↗ |
| Mar 5, 2025 | Jill Henrich | EVP, Chief Regulatory Officer | Sale | 1.1K | $7.00 | $7.4K | SEC ↗ |
| Nov 20, 2024 | Jill Henrich | EVP, Chief Regulatory Officer | Sale | 1.0K | $11.20 | $11.2K | SEC ↗ |
| Nov 20, 2024 | Eric J Hyllengren | EVP, CFO and COO | Sale | 1.4K | $11.20 | $15.3K | SEC ↗ |
| Nov 20, 2024 | Anhco Nguyen | President and CEO | Sale | 1.7K | $11.20 | $18.6K | SEC ↗ |
| Aug 20, 2024 | Pascal Touchon | President and CEO | Sale | 3.0K | $6.63 | $20.1K | SEC ↗ |
| Aug 20, 2024 | Anhco Nguyen | EVP, Chief Sci. & Tech Officer | Sale | 1.8K | $6.63 | $12.1K | SEC ↗ |
| Aug 20, 2024 | Amar Murugan | EVP, Chief Legal Officer | Sale | 1.2K | $6.63 | $7.7K | SEC ↗ |
| Aug 20, 2024 | Eric J Hyllengren | EVP, CFO | Sale | 1.1K | $6.63 | $7.1K | SEC ↗ |
Showing the 25 most recent of 222 Form 4 filings for Atara Biotherapeutics, Inc..
Most active ATRA insiders
- Isaac E. Ciechanover41 filings
- Joe Newell34 filings
- Pascal Touchon22 filings
- Utpal Koppikar22 filings
- Amar Murugan14 filings
Ask anything about ATRA insider activity
Use Trabud's AI agent to query Atara Biotherapeutics, Inc.'s Form 4 history in plain English — "Show me ATRA CEO purchases this year" or compare it against any other ticker.
Open the AI agentATRA insider trading FAQ
Are Atara Biotherapeutics, Inc. insiders buying or selling?
In the last 12 months, Atara Biotherapeutics, Inc. insiders reported 2 open-market purchases ($5.7M) and 9 sales ($3.9M) — net buying of $1.9M. Since January 2018, Trabud has recorded 222 Form 4 filings for ATRA: 11 buys ($7.5M) and 211 sells ($47.6M). Over the full record that is net selling of $40.1M.
How many insiders trade ATRA stock?
26 distinct insider filers — officers, directors, 10%+ owners, and investment groups filing jointly — have reported Form 4 transactions for Atara Biotherapeutics, Inc.. The most recent filing was accepted on Sep 4, 2026.
Where does Trabud get ATRA insider trading data?
All ATRA insider trading data comes directly from official SEC EDGAR Form 4 filings, which corporate insiders must submit within two business days of a transaction under Section 16(a) of the Securities Exchange Act of 1934.