Jim Simons
UPB

Jim Simons’s Upstream Bio Inc UPB Stock Holding History

Jim Simons’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 		$559K Buy
62,100
+45,700
+279% +$822K ﹤0.01% 2558
2025
Q4 		$445K Buy
+16,400
New +$408K ﹤0.01% 2620

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 $6.73T AUM 46.02% 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 $69.6B AUM 42.52% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.88T AUM 44.46% 1-Year Est. Return
Millennium Management
Millennium Management New York $240B AUM 35.51% 1-Year Est. Return

Jim Simons's UPB Position: Q1 2026 in Review

Jim Simons increased its Upstream Bio Inc (UPB) stake by 279% in Q1 2026, buying an estimated $822K and bringing the position to 62,100 shares worth $559K. The position accounts for ﹤0.01% of the portfolio, ranked #2558.

Jim Simons first reported a position in UPB in Q4 2025 and has held it in 2 quarters since. 140 funds tracked by Wall St. Rank hold UPB as of Q1 2026.

  • Jim Simons held 62,100 shares of Upstream Bio Inc worth $559K as of Q1 2026.
  • Jim Simons bought 45,700 Upstream Bio Inc shares in Q1 2026, an estimated $822K.
  • Upstream Bio Inc made up ﹤0.01% of Jim Simons's portfolio in Q1 2026, its #2558 holding.
  • Jim Simons first reported a position in Upstream Bio Inc in Q4 2025 and has held it in 2 quarters since.
  • 140 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q1 2026.

Based on Renaissance Technologies's 13F filing for Q1 2026, filed 14 May 2026.