XT
UPB

XTX Topco’s Upstream Bio Inc UPB Stock Holding History

XTX Topco’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 		$1.68M Buy
242,346
+33,069
+16% +$277K 0.02% 1292
2026
Q1 		$1.88M Buy
209,277
+194,186
+1,287% +$3.49M 0.03% 882
2025
Q4 		$410K Buy
+15,091
New +$376K 0.01% 1798
2025
Q2 		– Sell
-12,731
Closed -$77.9K – 3356
2025
Q1 		$77.9K Buy
+12,731
New +$122K ﹤0.01% 1918

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

XTX Topco's UPB Position: Q2 2026 in Review

XTX Topco increased its Upstream Bio Inc (UPB) stake by 16% in Q2 2026, buying an estimated $277K and bringing the position to 242,346 shares worth $1.68M. The position accounts for 0.02% of the portfolio, ranked #1292.

XTX Topco first reported a position in UPB in Q1 2025 and has held it in 4 quarters since. The position peaked at $1.88M in Q1 2026. 148 funds tracked by Wall St. Rank hold UPB as of Q2 2026.

  • XTX Topco held 242,346 shares of Upstream Bio Inc worth $1.68M as of Q2 2026.
  • XTX Topco bought 33,069 Upstream Bio Inc shares in Q2 2026, an estimated $277K.
  • Upstream Bio Inc made up 0.02% of XTX Topco's portfolio in Q2 2026, its #1292 holding.
  • XTX Topco first reported a position in Upstream Bio Inc in Q1 2025 and has held it in 4 quarters since.
  • XTX Topco's Upstream Bio Inc position peaked at $1.88M in Q1 2026.
  • 148 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q2 2026.

Based on XTX Topco's 13F filing for Q2 2026, filed 14 Aug 2026.