EcoR1 Capital, LLC insider trades: Atara Biotherapeutics (ATRA) stock buys and sales
Trades on the price chart
Daily close, with an arrow on each day they bought or sold
Companies
Where EcoR1 Capital, LLC reports to the SEC
and 12 more companies
Open-market buys and sales
59 trades reported on SEC Form 4, newest first
| Date | Stock | Type | Shares | Price | Value | Holding | Reported |
|---|---|---|---|---|---|---|---|
| May 7, 2026 | ATRA | ↑ Buy | 507,407 | $9.35 | $4.7M | See Note | May 11, 2026 (4d) |
| Apr 20, 2026 | TRAX | ↓ Sell | 4,705,575 | $13.81 | $65.0M | See Note | Apr 22, 2026 (2d) |
| Jan 12, 2026 | AKTS | ↑ Buy | 2,222,222 | $18.00 | $40.0M | See Note | Jan 12, 2026 (0d) |
| Jul 30, 2025 | ADAP | ↓ Sell | 64,052,538 | $0.11 | $6.9M | See Note | Jul 30, 2025 (0d) |
| May 19, 2025 | ZYME | ↑ Buy | 55,421 | $11.47 | $636K | See Note | May 19, 2025 (0d) |
| May 15, 2025 | ITOS | ↑ Buy | 4,958,978 | $7.80 | $38.7M | See Note | May 16, 2025 (1d) |
| May 6, 2025 | PRTA | ↓ Sell | 6,279,684 | $8.10 | $50.8M | See Note | May 6, 2025 (0d) |
| Apr 17, 2025 | ZYME | ↑ Buy | 128,713 | $11.32 | $1.5M | See Note | Apr 18, 2025 (1d) |
| Apr 4, 2025 | ZYME | ↑ Buy | 317,208 | $11.42 | $3.6M | See Note | Apr 7, 2025 (3d) |
| Apr 2, 2025 | ZYME | ↑ Buy | 127,415 | $11.75 | $1.5M | See Note | Apr 2, 2025 (0d) |
| Mar 26, 2025 | ZYME | ↑ Buy | 97,349 | $12.61 | $1.2M | See Note | Mar 27, 2025 (1d) |
| Mar 24, 2025 | ZYME | ↑ Buy | 127,198 | $12.92 | $1.6M | See Note | Mar 24, 2025 (0d) |
| Mar 19, 2025 | ZYME | ↑ Buy | 228,463 | $12.55 | $2.9M | See Note | Mar 19, 2025 (0d) |
| Mar 13, 2025 | ZYME | ↑ Buy | 1,081,980 | $12.13 | $13.1M | See Note | Mar 13, 2025 (0d) |
| Jan 17, 2025 | ZYME | ↑ Buy | 141,429 | $13.88 | $2.0M | See Note | Jan 21, 2025 (4d) |
| Jan 15, 2025 | ZYME | ↑ Buy | 167,654 | $13.59 | $2.3M | See Note | Jan 15, 2025 (0d) |
| Jan 10, 2025 | ZYME | ↑ Buy | 225,119 | $13.21 | $3.0M | See Note | Jan 10, 2025 (0d) |
| Jan 2, 2025 | ZYME | ↑ Buy | 363,369 | $14.64 | $5.3M | See Note | Jan 2, 2025 (0d) |
| Jan 2, 2025 | ANAB | ↑ Buy | 85,098 | $12.92 | $1.1M | See Note | Jan 2, 2025 (0d) |
| Dec 27, 2024 | ZYME | ↑ Buy | 130,309 | $14.44 | $1.9M | See Note | Dec 27, 2024 (0d) |
| Nov 7, 2024 | TNGX | ↓ Sell | 2,700,000 | $3.12 | $8.4M | See Note | Nov 8, 2024 (1d) |
| Aug 14, 2024 | ANAB | ↑ Buy | 273,972 | $36.50 | $10.0M | See Notes | Aug 16, 2024 (2d) |
| Jun 16, 2023 | ZYME | ↑ Buy | 3,350,000 | $8.12 | $27.2M | See Note | Jun 21, 2023 (5d) |
| Mar 28, 2023 | ZYME | ↑ Buy | 200,000 | $8.00 | $1.6M | See note | Mar 30, 2023 (2d) |
| Feb 21, 2023 | NUVB | ↑ Buy | 5,313,100 | $1.26 | $6.7M | See Notes | Sep 21, 2023 (212d) |
| Jan 20, 2023 | ZYME | ↑ Buy | 307,500 | $9.70 | $3.0M | See Note 1 | Jan 23, 2023 (3d) |
| Jan 18, 2023 | ZYME | ↑ Buy | 985,100 | $9.84 | $9.7M | See Note 1 | Jan 18, 2023 (0d) |
| Jan 11, 2023 | ZYME | ↑ Buy | 1,026,300 | $7.67 | $7.9M | See Note 1 | Jan 12, 2023 (1d) |
| Jan 11, 2023 | VYGR | ↓ Sell | 902,400 | $7.91 | $7.1M | See Note 1 | Jan 11, 2023 (0d) |
| Jun 23, 2022 | VYGR | ↑ Buy | 477,400 | $5.58 | $2.7M | See Note 1 | Jun 23, 2022 (0d) |
| May 5, 2022 | PRTA | ↑ Buy | 1,062,736 | $29.02 | $30.8M | See Notes | May 9, 2022 (4d) |
| May 5, 2022 | PRTA | ↓ Sell | 1,062,736 | $29.02 | $30.8M | See Note | May 9, 2022 (4d) |
| May 5, 2022 | ANAB | ↓ Sell | 668,237 | $21.63 | $14.5M | See Note | May 9, 2022 (4d) |
| May 5, 2022 | ANAB | ↑ Buy | 668,237 | $21.63 | $14.5M | See Notes | May 9, 2022 (4d) |
| Jan 12, 2022 | PRTA | ↑ Buy | 300,000 | $37.50 | $11.3M | See Note 1 | Jan 12, 2022 (0d) |
| Dec 10, 2021 | ODT | ↓ Sell | 5,887,610 | $1.65 | $9.7M | See Note 1 | Dec 10, 2021 (0d) |
| Dec 1, 2021 | ODT | ↑ Buy | 185,941 | $1.66 | $309K | See Note 1 | Dec 10, 2021 (9d) |
| Nov 24, 2021 | NUVB | ↑ Buy | 371,410 | $8.96 | $3.3M | See Notes 2 and 3 | Nov 30, 2021 (6d) |
| Nov 24, 2021 | NUVB | ↑ Buy | 21,758 | $7.69 | $167K | See Notes 2 and 4 | Nov 30, 2021 (6d) |
| Oct 1, 2021 | CRVS | ↓ Sell | 5,000,000 | $5.01 | $25.1M | See Note 2 | Oct 1, 2021 (0d) |
| Jul 31, 2021 | NUVB | ↓ Sell | 208,142 | $9.96 | $2.1M | See Notes 2 and 4 | Nov 30, 2021 (122d) |
| May 4, 2021 | ANAB | ↑ Buy | 221,500 | $23.24 | $5.1M | See Note 1 | May 4, 2021 (0d) |
| Apr 27, 2021 | ANAB | ↑ Buy | 147,300 | $23.63 | $3.5M | See Note 1 | Apr 27, 2021 (0d) |
| Apr 13, 2021 | NUVB | ↑ Buy | 406,019 | $9.89 | $4.0M | See Notes 1 and 2 | Apr 13, 2021 (0d) |
| Apr 13, 2021 | NUVB | ↑ Buy | 58,481 | $9.89 | $578K | See Notes 1 and 3 | Apr 13, 2021 (0d) |
| Apr 9, 2021 | PANA | ↑ Buy | 545,000 | $10.00 | $5.5M | Direct | Apr 13, 2021 (4d) |
| Mar 24, 2021 | PRTA | ↑ Buy | 875,000 | $20.75 | $18.2M | See Note 1 | Mar 25, 2021 (1d) |
| Mar 9, 2021 | ANAB | ↑ Buy | 3,308,800 | $18.93 | $62.6M | See Note 1 | Mar 10, 2021 (1d) |
| Feb 24, 2021 | PRTA | ↑ Buy | 55,200 | $21.24 | $1.2M | See Note 1 | Feb 25, 2021 (1d) |
| Feb 23, 2021 | ANAB | ↑ Buy | 29,500 | $25.48 | $752K | See Note 1 | Feb 25, 2021 (2d) |
Each row is one filing's trades in one stock, summed. Shares and prices are as filed, before any later stock split.
Other ATRA insiders
Open-market trades in the last 12 months
About EcoR1 Capital, LLC's insider trades
EcoR1 Capital, LLC is a 10% owner of Atara Biotherapeutics (ATRA). Since Mar 28, 2014, it has reported 48 open-market purchases worth $393.5M and 11 sales worth $222.9M on SEC Form 4. In the last 12 months: 2 buys ($44.7M) and 1 sale ($65.0M).
Its filings also include other transactions (4 filings), conversions (3 filings), option exercises (2 filings), shares withheld for taxes (1 filing). These aren't open-market trades and aren't counted above.
How to read insider trades
Officers, directors and owners of more than 10% of a company must report trades in its stock on SEC Form 4, usually within two business days. Purchases with their own money are the stronger signal: insiders sell for many reasons (taxes, diversification, a house), but buy for one. See every ATRA insider trade, the latest insider trades across the market, or cluster buys, when several insiders buy the same stock within days.