Samsara BioCapital’s Upstream Bio Inc UPB Stock Holding History

Samsara BioCapital’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
2026 Q2	$2.45M	Sell	353,717 -382,330	-52%	-$3.2M	0.2%	23
2026 Q1	$6.62M	Hold	736,047	–	–	0.64%	16
2025 Q4	$20M	Sell	736,047 -226,107	-24%	-$5.63M	2.06%	9
2025 Q3	$18.1M	Sell	962,154 -481,077	-33%	-$7.47M	2.36%	7
2025 Q2	$15.8M	Sell	1,443,231 -623,915	-30%	-$5.76M	3.24%	7
2025 Q1	$12.7M	Sell	2,067,146 -150,000	-7%	-$1.43M	2.26%	10
2024 Q4	$36.4M	Buy	+2,217,146	New	+$49.5M	5%	6

Other funds holding UPB

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

OrbiMed New York $5.4B AUM 163.13% 1-Year Est. Return

Norges Bank Oslo, Norway $1T AUM

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Decheng Capital Menlo Park, California $732M AUM 275.56% 1-Year Est. Return

Enavate Sciences Menlo Park, California $345M AUM 134.64% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Millennium Management New York $276B AUM 44.8% 1-Year Est. Return

D.E. Shaw & Co New York $210B AUM 57.28% 1-Year Est. Return

JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return

Samsara BioCapital's UPB Position: Q2 2026 in Review

Samsara BioCapital reduced its Upstream Bio Inc (UPB) stake by 52% in Q2 2026, selling an estimated $3.2M and leaving 353,717 shares worth $2.45M. The position accounts for 0.2% of the portfolio, ranked #23.

Samsara BioCapital first reported a position in UPB in Q4 2024 and has held it in 7 quarters since. The position peaked at $36.4M in Q4 2024. 149 funds tracked by Wall St. Rank hold UPB as of Q2 2026.

Samsara BioCapital held 353,717 shares of Upstream Bio Inc worth $2.45M as of Q2 2026.
Samsara BioCapital sold 382,330 Upstream Bio Inc shares in Q2 2026, an estimated $3.2M.
Upstream Bio Inc made up 0.2% of Samsara BioCapital's portfolio in Q2 2026, its #23 holding.
Samsara BioCapital first reported a position in Upstream Bio Inc in Q4 2024 and has held it in 7 quarters since.
Samsara BioCapital's Upstream Bio Inc position peaked at $36.4M in Q4 2024.
149 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q2 2026.

Based on Samsara BioCapital's 13F filing for Q2 2026, filed 14 Aug 2026.