EcoR1 Capital’s Upstream Bio Inc UPB Stock Holding History

EcoR1 Capital’s Portfolio UPB Stock Details UPB Fund Activity

Bought

Maintained

Sold

Quarter	Market Value	Status	Shares	Change in Stake	Trade Value	Portfolio Weight	Portfolio Position
2025 Q2	–	Sell	-60,000	Closed	-$367K	–	51
2025 Q1	$367K	Hold	60,000	–	–	0.02%	46
2024 Q4	$986K	Buy	+60,000	New	+$1.34M	0.04%	55

Other funds holding UPB

Fidelity Investments Boston, Massachusetts $1.9T AUM 41.92% 1-Year Est. Return

OrbiMed New York $5.05B AUM 125.28% 1-Year Est. Return

Altshuler Shaham Tel Aviv, Israel $5.54B AUM 44.68% 1-Year Est. Return

Decheng Capital Menlo Park, California $661M AUM 299.97% 1-Year Est. Return

TCM

TCG Crossover Management Palo Alto, California $3.5B AUM 1,165.83% 1-Year Est. Return

Enavate Sciences Menlo Park, California $352M AUM 220.14% 1-Year Est. Return

BCLSI

Bain Capital Life Sciences Investors Boston, Massachusetts $1.11B AUM 171.34% 1-Year Est. Return

VR Adviser New York $2.68B AUM 422.73% 1-Year Est. Return

Vanguard Group Malvern, Pennsylvania $6.9T AUM 27.45% 1-Year Est. Return

BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return

EcoR1 Capital's UPB Position: Q2 2025 in Review

EcoR1 Capital sold out of Upstream Bio Inc (UPB) in Q2 2025, closing a stake of 60,000 shares — an estimated $367K sold.

EcoR1 Capital first reported a position in UPB in Q4 2024 and held it in 2 quarters. The position peaked at $986K in Q4 2024. 83 funds tracked by Wall St. Rank hold UPB as of Q2 2025.

EcoR1 Capital reported no remaining Upstream Bio Inc position as of Q2 2025 after selling out during the quarter.
EcoR1 Capital sold 60,000 Upstream Bio Inc shares in Q2 2025, an estimated $367K.
EcoR1 Capital first reported a position in Upstream Bio Inc in Q4 2024 and held it in 2 quarters.
EcoR1 Capital's Upstream Bio Inc position peaked at $986K in Q4 2024.
83 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q2 2025.

Based on EcoR1 Capital's 13F filing for Q2 2025, filed 14 Aug 2025.