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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.

13F holders, Q4 2025

Institutional positions in Upstream Bio, Inc. as of Dec 31, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works

Institutional holders
133
+38 vs. Q3 2025
Shares held
51.2M
+6.71M (+15.1%) vs. Q3 2025
Total value
$1.39B
+$553.1M (+66.1%) vs. Q3 2025
New holders
46
42 more added
Sold out
8
33 more reduced

Compare with Q3 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting UPB on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.

Institutional holdersQ4 2025: 133 institutions
Q1 2021: 0 institutionsQ2 2021: 0 institutionsQ3 2021: 0 institutionsQ4 2021: 0 institutionsQ1 2022: 0 institutionsQ2 2022: 0 institutionsQ3 2022: 0 institutionsQ4 2022: 0 institutionsQ1 2023: 0 institutionsQ2 2023: 0 institutionsQ3 2023: 0 institutionsQ4 2023: 0 institutionsQ1 2024: 0 institutionsQ2 2024: 0 institutionsQ3 2024: 0 institutionsQ4 2024: 70 institutionsQ1 2025: 79 institutionsQ2 2025: 83 institutionsQ3 2025: 95 institutionsQ4 2025: 133 institutionsQ1 2026: 140 institutionsQ2 2026: 148 institutions
Value heldQ4 2025: $1.39B
Q1 2021: $0Q2 2021: $0Q3 2021: $0Q4 2021: $0Q1 2022: $0Q2 2022: $0Q3 2022: $0Q4 2022: $0Q1 2023: $0Q2 2023: $0Q3 2023: $0Q4 2023: $0Q1 2024: $0Q2 2024: $0Q3 2024: $0Q4 2024: $690.1MQ1 2025: $266.9MQ2 2025: $530.9MQ3 2025: $836.3MQ4 2025: $1.39BQ1 2026: $404.5MQ2 2026: $350.1M
Institutions holding UPB and their total value by quarter
QuarterHoldersValue
Q2 2026148$350.1M
Q1 2026140$404.5M
Q4 2025133$1.39B
Q3 202595$836.3M
Q2 202583$530.9M
Q1 202579$266.9M
Q4 202470$690.1M
Q3 20240$0
Q2 20240$0
Q1 20240$0
Q4 20230$0
Q3 20230$0
Q2 20230$0
Q1 20230$0
Q4 20220$0
Q3 20220$0
Q2 20220$0
Q1 20220$0
Q4 20210$0
Q3 20210$0
Q2 20210$0
Q1 20210$0

Institutions, Q4 2025

Shares, value and share of portfolio for each institution holding Upstream Bio, Inc.; share changes are against Q3 2025.

Institutions holding UPB in Q4 2025
InstitutionSharesValue% of portfolioChange in sharesAction
FMR LLC7,518,202$204.1M0.01%−568,211−7.0%Reduced
OrbiMed Advisors LLC5,693,589$154.6M3.16%00.0%Unchanged
BlackRock, Inc.3,344,504$90.8M0.00%+740,798+28.5%Added
Decheng Capital LLC3,143,078$85.3M11.48%−142,215−4.3%Reduced
Norges Bank2,882,647$78.3M0.01%+2,882,647New
Enavate Sciences GP, LLC2,459,703$66.8M13.18%00.0%Unchanged
Vanguard Group Inc2,388,439$64.8M0.00%−54,112−2.2%Reduced
UBS Group AG1,806,243$49.0M0.01%+1,533,972+563.4%Added
Janus Henderson Group PLC1,527,958$41.4M0.02%+1,527,958New
Altshuler Shaham Ltd1,341,540$36.4M0.56%−75,282−5.3%Reduced
Bain Capital Life Sciences Investors, LLC1,329,544$36.1M2.76%−1,109,994−45.5%Reduced
Omega Fund Management, LLC1,326,293$36.0M12.57%−30,000−2.2%Reduced
State Street Corp1,319,226$35.8M0.00%+204,645+18.4%Added
VR Adviser, LLC1,169,298$31.7M1.57%00.0%Unchanged
Wellington Management Group LLP894,733$24.3M0.00%−230,662−20.5%Reduced
Geode Capital Management, LLC851,908$23.1M0.00%+34,799+4.3%Added
Parkman Healthcare Partners LLC834,559$22.7M2.16%−8,943−1.1%Reduced
Pictet Asset Management Holding SA773,148$21.0M0.02%+773,148New
Woodline Partners LP760,252$20.6M0.08%+158,000+26.2%Added
Integral Health Asset Management, LLC750,000$20.4M1.03%+175,000+30.4%Added
TCG Crossover Management, LLC743,886$20.2M0.67%−1,373,217−64.9%Reduced
Samsara BioCapital, LLC736,047$20.0M2.06%−226,107−23.5%Reduced
Vestal Point Capital, LP720,000$19.5M0.72%+720,000New
Siren, L.L.C.588,450$16.0M0.48%−200,000−25.4%Reduced
Barclays PLC524,499$14.2M0.01%+439,184+514.8%Added
Millennium Management LLC517,264$14.0M0.01%+477,151+1,189.5%Added
Nantahala Capital Management, LLC494,971$13.4M0.80%−100,000−16.8%Reduced
Marshall Wace, LLP343,791$9.33M0.01%−524,208−60.4%Reduced
Goldman Sachs Group Inc333,481$9.05M0.00%+110,267+49.4%Added
Great Point Partners LLC300,000$8.14M2.64%00.0%Unchanged
Alyeska Investment Group, L.P.298,329$8.10M0.02%+298,329New
Jennison Associates LLC288,847$7.84M0.00%+288,847New
Charles Schwab Investment Management Inc284,931$7.74M0.00%+1030.0%Added
Northern Trust Corp236,799$6.43M0.00%−17,920−7.0%Reduced
Squadron Capital Management LLC230,650$6.26M2.79%+230,650New
Invesco Ltd.163,186$4.43M0.00%+145,996+849.3%Added
Boxer Capital Management, LLC150,000$4.07M0.89%+150,000New
Deutsche Bank AG127,815$3.47M0.00%+101,078+378.0%Added
Morgan Stanley122,068$3.31M0.00%+34,533+39.5%Added
SummitTX Capital, L.P.116,724$3.17M0.10%+4,320+3.8%Added
Schonfeld Strategic Advisors LLC115,807$3.14M0.02%−74,437−39.1%Reduced
JPMorgan Chase & Co110,280$2.99M0.00%+80,333+268.3%Added
American Century Companies Inc87,756$2.38M0.00%+16,216+22.7%Added
Bank of America Corp86,384$2.35M0.00%+30,911+55.7%Added
Bank of New York Mellon Corp84,853$2.30M0.00%−6,668−7.3%Reduced
Nuveen, LLC78,568$2.13M0.00%+8,686+12.4%Added
ExodusPoint Capital Management, LP75,402$2.05M0.02%+75,402New
Artia Global Partners LP68,653$1.86M0.30%+68,653New
Exome Asset Management LLC64,845$1.76M0.87%+12,885+24.8%Added
Ameriprise Financial Inc56,557$1.54M0.00%+56,557New
Susquehanna International Group, LLP55,841$1.52M0.00%+55,841New
Seven Grand Managers, LLC50,000$1.36M0.10%+50,000New
Y-Intercept (Hong Kong) Ltd46,559$1.26M0.03%+46,559New
Alps Advisors Inc44,376$1.20M0.01%+18,414+70.9%Added
Rhumbline Advisers41,523$1.13M0.00%−7,883−16.0%Reduced
Rafferty Asset Management, LLC38,683$1.05M0.00%+4,162+12.1%Added
Wells Fargo & Company36,794$999.0K0.00%+11,634+46.2%Added
Trexquant Investment LP31,049$843.0K0.01%+31,049New
Alliancebernstein L.P.31,010$841.9K0.00%+11,160+56.2%Added
AQR Capital Management LLC30,503$828.2K0.00%+549+1.8%Added
D. E. Shaw & Co., Inc.27,091$735.5K0.00%+27,091New
Swiss National Bank26,600$722.2K0.00%+26,600New
Diadema Partners LP20,500$556.6K0.33%+20,500New
MetLife Investment Management19,678$534.3K0.00%−2,013−9.3%Reduced
Price T Rowe Associates Inc19,636$534.0K0.00%+1,135+6.1%Added
PSP Research LLC17,634$478.8K0.42%+17,634New
Mirae Asset Global ETFs Holdings Ltd.17,491$475.3K0.00%+628+3.7%Added
Prelude Capital Management, LLC16,560$449.6K0.03%+825+5.2%Added
Renaissance Technologies LLC16,400$445.3K0.00%+16,400New
Quantinno Capital Management LP15,415$418.5K0.00%+526+3.5%Added
XTX Topco Ltd15,091$409.7K0.01%+15,091New
California State Teachers Retirement System14,652$397.8K0.00%+12,476+573.3%Added
Profund Advisors LLC14,582$395.9K0.01%+14,582New
Graham Capital Management, L.P.13,712$372.3K0.01%+13,712New
Legal & General Group Plc13,709$372.2K0.00%+10,785+368.8%Added
Citadel Advisors LLC13,420$364.4K0.00%+13,420New
DnB Asset Management AS12,793$347.3K0.00%+12,793New
Virtu Financial LLC12,246$332.0K0.01%+12,246New
Verition Fund Management LLC12,020$326.3K0.00%−34,981−74.4%Reduced
Mariner, LLC11,830$321.2K0.00%+897+8.2%Added
Creative Planning11,749$319.0K0.00%−2,517−17.6%Reduced
New York State Common Retirement Fund11,700$317.7K0.00%+5,400+85.7%Added
Two Sigma Investments, LP10,500$285.1K0.00%00.0%Unchanged
Intech Investment Management LLC10,396$282.3K0.00%00.0%Unchanged
Manufacturers Life Insurance Company, The10,147$275.5K0.00%−1,945−16.1%Reduced
Virtus Investment Advisers, Inc.9,801$266.1K0.07%−42−0.4%Reduced
STRS Ohio9,800$266.1K0.00%+9,800New
VARCOV Co.9,619$261.2K0.10%+9,619New
Police & Firemen's Retirement System of New Jersey9,456$256.7K0.00%+9+0.1%Added
Persistent Asset Partners Ltd8,907$241.8K0.12%+8,907New
China Universal Asset Management Co., Ltd.8,806$239.1K0.02%+8,806New
ProShare Advisors LLC8,354$226.8K0.00%+8,354New
SEI Investments Co8,087$219.6K0.00%+8,087New
Citigroup Inc6,949$188.7K0.00%−35,088−83.5%Reduced
SG Americas Securities, LLC5,518$150.0K0.00%+5,518New
BNP Paribas Arbitrage, SA4,976$135.1K0.00%−1,551−23.8%Reduced
CWM, LLC3,360$91.0K0.00%+19+0.6%Added
KLP Kapitalforvaltning AS2,900$78.7K0.00%+2,900New
Russell Investments Group, Ltd.2,823$76.6K0.00%−211−7.0%Reduced
Ameritas Investment Partners, Inc.2,741$74.4K0.00%00.0%Unchanged