EcoR1 Capital, LLC

SEC CIK: 0001587114
Latest filing: Aug 14, 2026

SEC filings (opens in a new tab)

UPB holding history

Upstream Bio, Inc. in every 13F filed by EcoR1 Capital, LLC, including the quarters it was sold out or no filing was made. Changes compare share counts with the previous calendar quarter.

UPB overview All 13F holders of UPB Full Q2 2026 holdings

Shares (Q2 2025): 0; Sold out in Q2 2025
Value: $0
% of portfolio: 0.0%
Quarters held: 2; Since Q4 2024

Holdings of UPB by EcoR1 Capital, LLC, by quarter
Quarter	Shares	Value	% of portfolio	Share change	Action	All holders
Q2 2025	0	$0	0.0%	−60,000−100.0%	Sold out	Holders
Q1 2025	60,000	$367.2K	<0.1%	00.0%	Unchanged	Holders
Q4 2024	60,000	$986.4K	<0.1%	+60,000	New	Holders