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Insider ActivityATRA
EcoR1 Capital, LLC, 10% Owner at Atara Biotherapeutics, Inc., bought $4.7M of ATRA
Updated Jun 14, 2026
EcoR1 Capital, LLC
10% Owner
Atara Biotherapeutics, Inc. ·
$ATRA
Transaction Details
| Insider | EcoR1 Capital, LLC |
|---|---|
| Title | 10% Owner |
| Company | Atara Biotherapeutics, Inc. |
| Ticker | ATRA |
| Transaction Type | Purchase |
| Transaction Date | 2026-05-07 |
| Shares Traded | 507,407 |
| Price Per Share | $9.35 |
| Total Value | $4.7M |
| Filed Date | 2026-05-11 |
| Accession Number | 0000935836-26-000239 |
Ownership Context
| Shares Owned After Transaction | 1,552,000 |
|---|---|
| Ownership Type | Indirect |
SEC Filing
Accession: 0000935836-26-000239
Other Insider Trades — ATRA
| Insider | Title | Action | Value | Date |
|---|---|---|---|---|
| HEIDEN WILLIAM K | Insider | traded | — | 2026-06-09 |
| Fust Matthew K | Insider | traded | — | 2026-06-09 |
| Ciongoli Gregory Austin | Insider | traded | — | 2026-06-09 |
| Grant-Huerta Yanina | Chief Accounting Officer | sold | $22K | 2026-05-18 |
| Nguyen AnhCo | President and CEO | sold | $48K | 2026-05-18 |
| Panacea Innovation Ltd | Insider | sold | $3.2M | 2026-05-07 |
Other Trades by EcoR1 Capital, LLC
| Ticker | Company | Action | Value | Date |
|---|---|---|---|---|
| TRAX | First Tracks Biotherapeutics, Inc. | sold | $65.0M | 2026-04-20 |
Full Ticker Profile
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Data sourced from SEC Form 4 insider trading filings. Transaction details are as reported to the Securities and Exchange Commission. This page does not constitute financial advice. StonkWhisper presents public records — it does not verify or guarantee the accuracy of SEC filings.
Last updated: June 14, 2026 at 07:12 UTC