Alyeska Investment Group
UPB

Alyeska Investment Group’s Upstream Bio Inc UPB Stock Holding History

Alyeska Investment Group’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 		– Sell
-298,329
Closed -$2.68M – 821
2026
Q1 		$2.68M Hold
298,329
– – 0.01% 535
2025
Q4 		$8.1M Buy
+298,329
New +$7.43M 0.02% 416
2025
Q3 		– Sell
-85,000
Closed -$933K – 744
2025
Q2 		$933K Hold
85,000
– – ﹤0.01% 509
2025
Q1 		$520K Hold
85,000
– – ﹤0.01% 466
2024
Q4 		$1.4M Buy
+85,000
New +$1.9M 0.01% 480

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

Alyeska Investment Group's UPB Position: Q2 2026 in Review

Alyeska Investment Group sold out of Upstream Bio Inc (UPB) in Q2 2026, closing a stake of 298,329 shares — an estimated $2.68M sold.

Alyeska Investment Group first reported a position in UPB in Q4 2024 and held it in 5 quarters. The position peaked at $8.1M in Q4 2025. 148 funds tracked by Wall St. Rank hold UPB as of Q2 2026.

  • Alyeska Investment Group reported no remaining Upstream Bio Inc position as of Q2 2026 after selling out during the quarter.
  • Alyeska Investment Group sold 298,329 Upstream Bio Inc shares in Q2 2026, an estimated $2.68M.
  • Alyeska Investment Group first reported a position in Upstream Bio Inc in Q4 2024 and held it in 5 quarters.
  • Alyeska Investment Group's Upstream Bio Inc position peaked at $8.1M in Q4 2025.
  • 148 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q2 2026.

Based on Alyeska Investment Group's 13F filing for Q2 2026, filed 14 Aug 2026.