EcoR1 Capital, LLC

10% Owner · 2 filings · Latest: May 7, 2026

Atara Biotherapeutics, Inc.

First Tracks Biotherapeutics, Inc.

Ticker	Owner	Relationship	Date	Transaction	Cost	#Shares	Value ($)	#Shares Total	SEC Filing
ATRA	EcoR1 Capital, LLC	10% Owner	May 7, 2026	Purchase	$9.35	507,407	$4.7M	1,552,000	May 11 9:34 PM
TRAX	EcoR1 Capital, LLC	10% Owner	Apr 20, 2026	Sale	$13.81	4,705,575	$65.0M	3,174,519	Apr 22 9:07 PM