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Upstream Bio, Inc.

UPB
Exchange
Nasdaq
Industry
Pharmaceutical Preparations
SEC CIK
0002022626

In the last 90 days, Upstream Bio, Inc. insiders filed 0 open-market purchases and 5 sales; 148 institutions reported holding it in 13F filings for Q2 2026, worth $350.1M in total; no superinvestor holds it.

Q1 2026 vs. Q4 2025

How the institutions holding Upstream Bio, Inc. changed between Q4 2025 and Q1 2026.

All holders in Q1 2026All holders in Q4 2025

13F holders of UPB: Q4 2025 compared with Q1 2026
MeasureQ4 2025Of which not filed for Q1 2026Q1 2026Change
Holders1333140+10
Shares51.2M5.27M44.9M−1.02M (−2.2%)
Value$1.39B$143.1M$404.5M−$841.8M (−67.5%)

3 institutions that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so the changes leave them out.

New holders (47)

Institutions that held Upstream Bio, Inc. at the end of Q1 2026 but not at the end of Q4 2025.

Institutions new to UPB in Q1 2026
InstitutionSharesValue% of portfolio
Vanguard Capital Management LLC1,873,574$16.9M0.00%
SEB Asset Management AB878,473$7.91M0.03%
Vanguard Portfolio Management LLC727,711$6.55M0.00%
HSBC Holdings PLC640,326$5.76M0.00%
Qube Research & Technologies Ltd619,321$5.57M0.01%
Sphera Funds Management Ltd.358,000$3.22M0.55%
Propel Bio Management, LLC341,779$3.10M1.95%
Jump Financial, LLC319,400$2.87M0.04%
Prosight Management, LP241,123$2.17M0.36%
Vanguard Fiduciary Trust Co224,157$2.02M0.00%
Arrowstreet Capital, Limited Partnership185,087$1.67M0.00%
Point72 Asset Management, L.P.178,168$1.60M0.00%
Dimensional Fund Advisors LP80,002$719.5K0.00%
Simplify Asset Management Inc.77,793$700.1K0.01%
EntryPoint Capital, LLC73,568$662.1K0.19%
Squarepoint Ops LLC44,626$401.6K0.00%
State of Wisconsin Investment Board41,671$375.0K0.00%
Gsa Capital Partners LLP39,232$353.0K0.02%
Stonepine Capital Management, LLC35,000$315.0K0.28%
ADAR1 Capital Management, LLC35,000$315.0K0.02%
Aquatic Capital Management LLC31,484$283.4K0.01%
Bleakley Financial Group, LLC28,864$259.8K0.00%
Axq Capital, LP27,503$247.5K0.03%
Tudor Investment Corp Et Al26,412$237.7K0.00%
Martingale Asset Management L P26,223$236.0K0.01%
Victory Capital Management Inc25,866$232.8K0.00%
Entropy Technologies, LP23,336$210.0K0.01%
Man Group plc21,154$190.4K0.00%
Franklin Resources Inc14,589$131.3K0.00%
Vanguard Global Advisers, LLC13,059$117.5K0.00%
CI Private Wealth, LLC12,157$109.4K0.00%
Shay Capital LLC10,000$90.0K0.01%
Vanguard Asset Management, Ltd9,250$83.3K0.00%
Vanguard Investments Australia, Ltd.4,096$36.9K0.00%
Rockefeller Capital Management L.P.738$6.64K0.00%
Quantbot Technologies LP663$5.97K0.00%
Zurcher Kantonalbank (Zurich Cantonalbank)477$4.29K0.00%
MAI Capital Management171$1.54K0.00%
Natixis120$1.08K0.00%
Wealth Preservation Advisors, LLC86$7740.00%
Farther Finance Advisors, LLC81$7540.00%
Ameritas Advisory Services, LLC31$2790.00%
Caitong International Asset Management Co., Ltd23$2070.00%
Root Financial Partners, LLC20$1800.00%
SJS Investment Consulting Inc.2$180.00%
Freestone Grove Partners LP1$90.00%
Covestor Ltd4$00.00%

Sold out (37)

Institutions that held Upstream Bio, Inc. at the end of Q4 2025 and filed for Q1 2026 without it.

Not filed for Q1 2026 yet (3)

Institutions that held Upstream Bio, Inc. at the end of Q4 2025 and haven't filed a 13F for Q1 2026. Not filing isn't selling, so they aren't counted as sold out.

Institutions holding UPB in Q4 2025 that haven't filed for Q1 2026
InstitutionShares, Q4 2025Value, Q4 2025
Norges Bank2,882,647$78.3M
Vanguard Group Inc2,388,439$64.8M
Global Retirement Partners, LLC273$7.41K