EcoR1 Capital, LLC

10% owner at TScan Therapeutics, Inc. · on record since Jun 5, 2023
10% owner at Mersana Therapeutics, Inc. · on record since Jul 31, 2023
10% owner at Mirati Therapeutics, Inc. · on record since Dec 27, 2023
10% owner at Tango Therapeutics, Inc. · on record since Oct 16, 2023
10% owner at Adaptimmune Therapeutics PLC · on record since Mar 26, 2024
10% owner at GENVEC INC · on record since Nov 27, 2013
Director at Zymeworks Inc. · on record since Dec 27, 2024
Director at ANAPTYSBIO, INC · on record since Apr 27, 2021
10% owner at iTeos Therapeutics, Inc. · on record since May 16, 2025
Director at ATECH (PARENT) RESOLUTION CORP. · on record since Jan 12, 2026
10% owner at ATECH (PARENT) RESOLUTION CORP. · on record since Jan 8, 2026
10% owner at First Tracks Biotherapeutics, Inc. · on record since Apr 22, 2026
10% owner at Atara Biotherapeutics, Inc. · on record since May 11, 2026
10% owner at CELADON GROUP INC · on record since Jun 30, 2015
10% owner at PROTHENA CORP PUBLIC LTD CO · on record since Aug 27, 2019
Director at Nuvation Bio Inc. · on record since Jun 30, 2020
10% owner at Nuvation Bio Inc. · on record since Jun 30, 2020
10% owner at Surface Oncology, Inc. · on record since May 29, 2020
10% owner at · on record since Jun 25, 2020
10% owner at · on record since Feb 25, 2021
10% owner at · on record since Sep 22, 2021
10% owner at · on record since Nov 18, 2021
10% owner at · on record since Apr 25, 2022
10% owner at · on record since Nov 1, 2022
10% owner at · on record since Jan 6, 2023
Affiliate of Director at · on record since Nov 30, 2021

Insider trading activity of EcoR1 Capital, LLC

Transactions on record: 123; since Mar 28, 2014

Open-market buys: 77; $330M

Open-market sells: 24; $222.7M

Companies traded: 16; last filing May 11, 2026

Figures computed from official regulatory filings — .

Companies where EcoR1 Capital, LLC has traded

1 tx · $4.7M · May 11, 2026
1 tx · $65M · Apr 22, 2026
3 tx · $6.7M · Jul 30, 2025
42 tx · $190.7M · May 19, 2025
2 tx · $38.7M · May 16, 2025
19 tx · $165.5M · May 6, 2025
9 tx · $103.4M · Jan 2, 2025
2 tx · Dec 23, 2024
3 tx · $8.4M · Nov 8, 2024
5 tx · $9.8M · Jan 11, 2023
5 tx · $10M · Dec 10, 2021
19 tx · $34.5M · Nov 30, 2021
2 tx · $25M · Oct 1, 2021
1 tx · $2.4M · Sep 3, 2020

Track record of EcoR1 Capital, LLC

Statistical track record

Free account

Open-market buys: 81

Last buy: May 7, 2026

Win rates, median returns and the proven-insider analysis come with a free account.

Transaction history of EcoR1 Capital, LLC

Co-insiders of EcoR1 Capital, LLC

This page republishes public regulatory disclosures.

Company	Filed	Type	Qty	Price	Value · USD	Signals	Src
Atara Biotherapeutics, Inc.Listing on record	May 11, 2026	Buy	507,407	9.35 USD	$4.7M	conv 34	SEC
First Tracks Biotherapeutics, Inc.Listing unverified	Apr 22, 2026	Sell	4,705,575	13.81 USD	$65M	Unusual size	SEC
Adaptimmune Therapeutics PLCListing unverified	Jul 30, 2025	Sell	-27,433,338	0.10 USD	$2.7M		SEC
Adaptimmune Therapeutics PLCListing unverified	Jul 30, 2025	Sell	-33,931,740	0.11 USD	$3.7M		SEC
Adaptimmune Therapeutics PLCListing unverified	Jul 30, 2025	Sell	-2,687,460	0.10 USD	$268.7K		SEC
Zymeworks Inc.Listing unverified	May 19, 2025	Buy	49,502	11.43 USD	$565.8K	conv 19	SEC
Zymeworks Inc.Listing unverified	May 19, 2025	Buy	5,919	11.78 USD	$69.7K	conv 19	SEC
iTeos Therapeutics, Inc.Listing unverified	May 16, 2025	Buy	1,658,978	7.41 USD	$12.3M	conv 56Unusual size	SEC
iTeos Therapeutics, Inc.Listing unverified	May 16, 2025	Buy	3,300,000	8.00 USD	$26.4M	conv 60Unusual size	SEC
PROTHENA CORP PUBLIC LTD COListing on record	May 6, 2025	Sell	-977,693	8.11 USD	$7.9M		SEC
PROTHENA CORP PUBLIC LTD COListing on record	May 6, 2025	Sell	-3,317,938	8.36 USD	$27.7M	Unusual size	SEC
PROTHENA CORP PUBLIC LTD COListing on record	May 6, 2025	Sell	-1,984,053	7.64 USD	$15.2M		SEC
Zymeworks Inc.Listing unverified	Apr 18, 2025	Buy	73,953	11.16 USD	$825.3K	conv 20	SEC
Zymeworks Inc.Listing unverified	Apr 18, 2025	Buy	54,760	11.52 USD	$630.8K	conv 19	SEC
Zymeworks Inc.Listing unverified	Apr 2, 2025	Buy	4,397	11.75 USD	$51.7K	conv 20	SEC
Zymeworks Inc.Listing unverified	Apr 2, 2025	Buy	48,658	11.60 USD	$564.4K	conv 19	SEC
Zymeworks Inc.Listing unverified	Apr 2, 2025	Buy	74,360	11.85 USD	$881.2K	conv 20	SEC
Zymeworks Inc.Listing unverified	Mar 27, 2025	Buy	53,501	12.91 USD	$690.7K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 27, 2025	Buy	43,848	12.24 USD	$536.7K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 24, 2025	Buy	31,033	12.78 USD	$396.6K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 24, 2025	Buy	22,689	13.08 USD	$296.8K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 24, 2025	Buy	73,476	12.93 USD	$950K	conv 20	SEC
Zymeworks Inc.Listing unverified	Mar 19, 2025	Buy	56,277	12.23 USD	$688.3K	conv 22	SEC
Zymeworks Inc.Listing unverified	Mar 19, 2025	Buy	58,306	12.64 USD	$737K	conv 20	SEC
Zymeworks Inc.Listing unverified	Mar 19, 2025	Buy	113,880	12.65 USD	$1.4M	conv 20	SEC

Company	Filed	Type	Qty	Price	Value · USD	Signals	Src
Atara Biotherapeutics, Inc.Listing on record	May 11, 2026	Buy	507,407	9.35 USD	$4.7M	conv 34	SEC
First Tracks Biotherapeutics, Inc.Listing unverified	Apr 22, 2026	Sell	4,705,575	13.81 USD	$65M	Unusual size	SEC
Adaptimmune Therapeutics PLCListing unverified	Jul 30, 2025	Sell	-27,433,338	0.10 USD	$2.7M		SEC
Adaptimmune Therapeutics PLCListing unverified	Jul 30, 2025	Sell	-33,931,740	0.11 USD	$3.7M		SEC
Adaptimmune Therapeutics PLCListing unverified	Jul 30, 2025	Sell	-2,687,460	0.10 USD	$268.7K		SEC
Zymeworks Inc.Listing unverified	May 19, 2025	Buy	49,502	11.43 USD	$565.8K	conv 19	SEC
Zymeworks Inc.Listing unverified	May 19, 2025	Buy	5,919	11.78 USD	$69.7K	conv 19	SEC
iTeos Therapeutics, Inc.Listing unverified	May 16, 2025	Buy	1,658,978	7.41 USD	$12.3M	conv 56Unusual size	SEC
iTeos Therapeutics, Inc.Listing unverified	May 16, 2025	Buy	3,300,000	8.00 USD	$26.4M	conv 60Unusual size	SEC
PROTHENA CORP PUBLIC LTD COListing on record	May 6, 2025	Sell	-977,693	8.11 USD	$7.9M		SEC
PROTHENA CORP PUBLIC LTD COListing on record	May 6, 2025	Sell	-3,317,938	8.36 USD	$27.7M	Unusual size	SEC
PROTHENA CORP PUBLIC LTD COListing on record	May 6, 2025	Sell	-1,984,053	7.64 USD	$15.2M		SEC
Zymeworks Inc.Listing unverified	Apr 18, 2025	Buy	73,953	11.16 USD	$825.3K	conv 20	SEC
Zymeworks Inc.Listing unverified	Apr 18, 2025	Buy	54,760	11.52 USD	$630.8K	conv 19	SEC
Zymeworks Inc.Listing unverified	Apr 2, 2025	Buy	4,397	11.75 USD	$51.7K	conv 20	SEC
Zymeworks Inc.Listing unverified	Apr 2, 2025	Buy	48,658	11.60 USD	$564.4K	conv 19	SEC
Zymeworks Inc.Listing unverified	Apr 2, 2025	Buy	74,360	11.85 USD	$881.2K	conv 20	SEC
Zymeworks Inc.Listing unverified	Mar 27, 2025	Buy	53,501	12.91 USD	$690.7K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 27, 2025	Buy	43,848	12.24 USD	$536.7K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 24, 2025	Buy	31,033	12.78 USD	$396.6K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 24, 2025	Buy	22,689	13.08 USD	$296.8K	conv 19	SEC
Zymeworks Inc.Listing unverified	Mar 24, 2025	Buy	73,476	12.93 USD	$950K	conv 20	SEC
Zymeworks Inc.Listing unverified	Mar 19, 2025	Buy	56,277	12.23 USD	$688.3K	conv 22	SEC
Zymeworks Inc.Listing unverified	Mar 19, 2025	Buy	58,306	12.64 USD	$737K	conv 20	SEC
Zymeworks Inc.Listing unverified	Mar 19, 2025	Buy	113,880	12.65 USD	$1.4M	conv 20	SEC