Insiders who reported open-market trades in the last 12 months at the companies EcoR1 Capital, LLC files at. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
EcoR1 Capital, LLC is an investment firm, tracked as 10% Owner of Atara Biotherapeutics, Inc. (ATRA). InsiderAlpha holds 8 primary Form 4 filings for it, the earliest from 2024, updated as new SEC EDGAR filings are processed.
When did EcoR1 Capital, LLC last file a Form 4?
The most recent primary Form 4 on record is dated 11 May 2026, one of 8 filings going back to 2024.
Has EcoR1 Capital, LLC been buying or selling stock?
Recorded transactions: 7 open-market purchases ($96.63M) and 7 open-market sales ($80.33M) across all tracked filings.
EcoR1 Capital, LLC is 10% Owner of Atara Biotherapeutics, Inc. (ATRA). 8 SEC Form 4 filings on record going back to 2024, most recently on 11 May 2026. Most recent open-market trade: bought $4.74M of ATRA on 11 May 2026. Lifetime open-market purchases: $96.63M. Lifetime open-market sales: $80.33M.
Recent transactions
17
The latest 17 SEC Form 4 transactions reported by EcoR1 Capital, LLC.
InsiderAlpha's records for EcoR1 Capital, LLC go back to 2024: 8 primary Form 4 filings, an average of 2.7 per year. The typical open-market purchase is $13.80M (7 buys totaling $96.63M). The largest single buy on record is $50.00M of ZYME in 2024. Sales side: 7 recorded sales totaling $80.33M, so the filing history runs buy-heavy by dollar value. No recorded transaction carries a Rule 10b5-1 plan flag. An absent flag does not establish whether a transaction was pre-arranged or discretionary.
