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
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 $1.9T AUM 41.92% 1-Year Est. Return
O
OrbiMed New York $5.05B AUM 125.28% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
DC
Decheng Capital Menlo Park, California $661M AUM 299.97% 1-Year Est. Return
ES
Enavate Sciences Menlo Park, California $352M AUM 220.14% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
YIH
Y-Intercept (HK) Hong Kong $5.05B AUM 17.89% 1-Year Est. Return
Federated Hermes
Federated Hermes Pittsburgh, Pennsylvania $61.5B AUM 30.7% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
Millennium Management
Millennium Management New York $240B AUM 35.51% 1-Year Est. Return

XTX Topco's UPB Position: Q1 2026 in Review

XTX Topco increased its Upstream Bio Inc (UPB) stake by 1,287% in Q1 2026, buying an estimated $3.49M and bringing the position to 209,277 shares worth $1.88M. The position accounts for 0.03% of the portfolio, ranked #882.

XTX Topco first reported a position in UPB in Q1 2025 and has held it in 3 quarters since. 140 funds tracked by Wall St. Rank hold UPB as of Q1 2026.

  • XTX Topco held 209,277 shares of Upstream Bio Inc worth $1.88M as of Q1 2026.
  • XTX Topco bought 194,186 Upstream Bio Inc shares in Q1 2026, an estimated $3.49M.
  • Upstream Bio Inc made up 0.03% of XTX Topco's portfolio in Q1 2026, its #882 holding.
  • XTX Topco first reported a position in Upstream Bio Inc in Q1 2025 and has held it in 3 quarters since.
  • 140 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q1 2026.

Based on XTX Topco's 13F filing for Q1 2026, filed 15 May 2026.