BCLSI
UPB

Bain Capital Life Sciences Investors’s Upstream Bio Inc UPB Stock Holding History

Bain Capital Life Sciences Investors’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 		$4.16M Sell
600,949
-266,262
-31% -$2.23M 0.25% 20
2026
Q1 		$7.8M Sell
867,211
-462,333
-35% -$8.32M 0.7% 18
2025
Q4 		$36.1M Sell
1,329,544
-1,109,994
-46% -$27.6M 2.76% 7
2025
Q3 		$45.9M Hold
2,439,538
– – 3.05% 9
2025
Q2 		$26.8M Buy
2,439,538
+144,216
+6% +$1.33M 3.35% 11
2025
Q1 		$14M Hold
2,295,322
– – 2.08% 11
2024
Q4 		$37.7M Buy
+2,295,322
New +$51.3M 4.44% 8

Other funds holding UPB

Fidelity Investments
Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return
O
OrbiMed New York $5.4B AUM 163.13% 1-Year Est. Return
Norges Bank
Norges Bank Oslo, Norway $1T AUM
BlackRock
BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return
DC
Decheng Capital Menlo Park, California $732M AUM 275.56% 1-Year Est. Return
ES
Enavate Sciences Menlo Park, California $345M AUM 134.64% 1-Year Est. Return
Vanguard Capital Management
Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM
Millennium Management
Millennium Management New York $276B AUM 44.8% 1-Year Est. Return
D.E. Shaw & Co
D.E. Shaw & Co New York $210B AUM 57.28% 1-Year Est. Return
JP Morgan Chase
JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return

Bain Capital Life Sciences Investors's UPB Position: Q2 2026 in Review

Bain Capital Life Sciences Investors reduced its Upstream Bio Inc (UPB) stake by 31% in Q2 2026, selling an estimated $2.23M and leaving 600,949 shares worth $4.16M. The position accounts for 0.25% of the portfolio, ranked #20.

Bain Capital Life Sciences Investors first reported a position in UPB in Q4 2024 and has held it in 7 quarters since. The position peaked at $45.9M in Q3 2025. 148 funds tracked by Wall St. Rank hold UPB as of Q2 2026.

  • Bain Capital Life Sciences Investors held 600,949 shares of Upstream Bio Inc worth $4.16M as of Q2 2026.
  • Bain Capital Life Sciences Investors sold 266,262 Upstream Bio Inc shares in Q2 2026, an estimated $2.23M.
  • Upstream Bio Inc made up 0.25% of Bain Capital Life Sciences Investors's portfolio in Q2 2026, its #20 holding.
  • Bain Capital Life Sciences Investors first reported a position in Upstream Bio Inc in Q4 2024 and has held it in 7 quarters since.
  • Bain Capital Life Sciences Investors's Upstream Bio Inc position peaked at $45.9M in Q3 2025.
  • 148 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q2 2026.

Based on Bain Capital Life Sciences Investors's 13F filing for Q2 2026, filed 14 Aug 2026.