EcoR1 Capital, LLC
10% Owner · Atara Biotherapeutics, Inc.
Every open-market stock purchase EcoR1 Capital, LLC has reported to the SEC on Form 4 that met our signal bar, parsed straight from the filings. Insiders sell for many reasons, but they buy with their own money for one — this page tracks where those buys landed inside insider clusters and how the prices paid compare to where the stock trades now.
Where the buys stand today
- ITOSiTeos Therapeutics, Inc.
2 purchases totalling $38.7M at an average of $7.80 per share. See all insider buying in ITOS →
Avg price paid$7.80Latest price—Market capUnknown - ZYMEZymeworks Inc.
26 purchases totalling $23.6M at an average of $13.26 per share. See all insider buying in ZYME →
Avg price paid$13.26Latest price—Market cap$1.9B - ANABANAPTYSBIO, INC
3 purchases totalling $11.0M at an average of $31.25 per share. See all insider buying in ANAB →
Avg price paid$31.25Latest price—Market capUnknown - ATRA+16.4% vs price paidAtara Biotherapeutics, Inc.
One purchase totalling $4.7M at an average of $9.35 per share; the stock last traded at $10.88. See all insider buying in ATRA →
Avg price paid$9.35Latest price$10.88Market cap$98.0M
Cluster participation
Buys that landed within days of other insiders buying the same stock — the pattern this site exists to catch.
All reported buys
| Date | Ticker | Shares | Price | Value | Filing |
|---|---|---|---|---|---|
| May 7, 2026 | 507,407 | $9.35 | $4.7M | SEC ↗ | |
| May 15, 2025 | 49,502 | $11.43 | $565.8K | SEC ↗ | |
| May 15, 2025 | 3,300,000 | $8.00 | $26.4M | SEC ↗ | |
| May 14, 2025 | 1,658,978 | $7.41 | $12.3M | SEC ↗ | |
| Apr 17, 2025 | ZYMEcluster | 54,760 | $11.52 | $630.8K | SEC ↗ |
| Apr 16, 2025 | ZYMEcluster | 73,953 | $11.16 | $825.3K | SEC ↗ |
| Apr 2, 2025 | ZYMEcluster | 74,360 | $11.85 | $881.2K | SEC ↗ |
| Apr 1, 2025 | ZYMEcluster | 48,658 | $11.60 | $564.4K | SEC ↗ |
| Mar 26, 2025 | ZYMEcluster | 43,848 | $12.24 | $536.7K | SEC ↗ |
| Mar 25, 2025 | ZYMEcluster | 53,501 | $12.91 | $690.7K | SEC ↗ |
| Mar 24, 2025 | ZYMEcluster | 22,689 | $13.08 | $296.8K | SEC ↗ |
| Mar 21, 2025 | ZYMEcluster | 31,033 | $12.78 | $396.6K | SEC ↗ |
| Mar 20, 2025 | ZYMEcluster | 73,476 | $12.93 | $950.0K | SEC ↗ |
| Mar 19, 2025 | ZYMEcluster | 58,306 | $12.64 | $737.0K | SEC ↗ |
| Mar 18, 2025 | ZYMEcluster | 113,880 | $12.65 | $1.4M | SEC ↗ |
| Mar 17, 2025 | ZYMEcluster | 56,277 | $12.23 | $688.3K | SEC ↗ |
| Jan 17, 2025 | 19,748 | $13.87 | $273.9K | SEC ↗ | |
| Jan 16, 2025 | 121,681 | $13.89 | $1.7M | SEC ↗ | |
| Jan 15, 2025 | 39,029 | $14.01 | $546.8K | SEC ↗ | |
| Jan 14, 2025 | 54,500 | $13.56 | $739.0K | SEC ↗ | |
| Jan 13, 2025 | 74,125 | $13.39 | $992.5K | SEC ↗ | |
| Jan 10, 2025 | 204,098 | $13.13 | $2.7M | SEC ↗ | |
| Jan 8, 2025 | 21,021 | $14.07 | $295.8K | SEC ↗ | |
| Jan 2, 2025 | 157,880 | $14.78 | $2.3M | SEC ↗ | |
| Dec 31, 2024 | 146,501 | $14.57 | $2.1M | SEC ↗ | |
| Dec 31, 2024 | 13,268 | $12.93 | $171.6K | SEC ↗ | |
| Dec 30, 2024 | 58,988 | $14.47 | $853.6K | SEC ↗ | |
| Dec 30, 2024 | 65,184 | $12.92 | $842.2K | SEC ↗ | |
| Dec 27, 2024 | 101,659 | $14.49 | $1.5M | SEC ↗ | |
| Dec 26, 2024 | 16,692 | $14.38 | $240.0K | SEC ↗ | |
| Dec 24, 2024 | 11,958 | $14.12 | $168.8K | SEC ↗ | |
| Aug 14, 2024 | 273,972 | $36.50 | $10.0M | SEC ↗ |
Get alerted the next time EcoR1 Capital, LLC — or any insider — buys
We watch every Form 4 as it hits SEC EDGAR and alert you when insiders cluster into the same stock.
About this data
Figures are parsed from EcoR1 Capital, LLC's Form 4 filings on SEC EDGAR (CIK 1587114) and cover open-market purchases (transaction code P) — grants, option exercises, and sales are excluded, which is why totals here can differ from raw filing counts. Every row links to its source document.
This page is informational and reflects public filing data. It is not investment advice.