Arrowstreet Capital’s Upstream Bio Inc UPB Stock Holding History

Arrowstreet Capital’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	$2.48M	Buy	357,756 +172,669	+93%	+$1.45M	﹤0.01%	1481
2026 Q1	$1.67M	Buy	+185,087	New	+$3.33M	﹤0.01%	1442

Other funds holding UPB

Fidelity Investments Boston, Massachusetts $2.3T AUM 54.33% 1-Year Est. Return

OrbiMed New York $5.4B AUM 163.13% 1-Year Est. Return

Norges Bank Oslo, Norway $1T AUM

BlackRock New York $6.73T AUM 46.02% 1-Year Est. Return

Decheng Capital Menlo Park, California $732M AUM 275.56% 1-Year Est. Return

Enavate Sciences Menlo Park, California $345M AUM 134.64% 1-Year Est. Return

Vanguard Capital Management Malvern, Pennsylvania $4.68T AUM

Millennium Management New York $276B AUM 44.8% 1-Year Est. Return

D.E. Shaw & Co New York $210B AUM 57.28% 1-Year Est. Return

JP Morgan Chase New York $1.81T AUM 41.13% 1-Year Est. Return

Arrowstreet Capital's UPB Position: Q2 2026 in Review

Arrowstreet Capital increased its Upstream Bio Inc (UPB) stake by 93% in Q2 2026, buying an estimated $1.45M and bringing the position to 357,756 shares worth $2.48M. The position accounts for ﹤0.01% of the portfolio, ranked #1481.

Arrowstreet Capital first reported a position in UPB in Q1 2026 and has held it in 2 quarters since. 148 funds tracked by Wall St. Rank hold UPB as of Q2 2026.

Arrowstreet Capital held 357,756 shares of Upstream Bio Inc worth $2.48M as of Q2 2026.
Arrowstreet Capital bought 172,669 Upstream Bio Inc shares in Q2 2026, an estimated $1.45M.
Upstream Bio Inc made up ﹤0.01% of Arrowstreet Capital's portfolio in Q2 2026, its #1481 holding.
Arrowstreet Capital first reported a position in Upstream Bio Inc in Q1 2026 and has held it in 2 quarters since.
148 funds tracked by Wall St. Rank held Upstream Bio Inc as of Q2 2026.

Based on Arrowstreet Capital's 13F filing for Q2 2026, filed 13 Aug 2026.