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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, Q3 2025

Institutional positions in Upstream Bio, Inc. as of Sep 30, 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
95
+13 vs. Q2 2025
Shares held
44.5M
−2.92M (−6.2%) vs. Q2 2025
Total value
$836.3M
+$316.1M (+60.7%) vs. Q2 2025
New holders
22
38 more added
Sold out
9
22 more reduced

1 institution that held it in Q2 2025 haven't filed for Q3 2025 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q2 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 holdersQ3 2025: 95 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 heldQ3 2025: $836.3M
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, Q3 2025

Shares, value and share of portfolio for each institution holding Upstream Bio, Inc.; share changes are against Q2 2025.

Institutions holding UPB in Q3 2025
InstitutionSharesValue% of portfolioChange in sharesAction
FMR LLC8,086,413$152.1M0.01%+149,533+1.9%Added
OrbiMed Advisors LLC5,693,589$107.1M2.57%00.0%Unchanged
Decheng Capital LLC3,285,293$61.8M10.78%00.0%Unchanged
BlackRock, Inc.2,603,706$49.0M0.00%+507,200+24.2%Added
Enavate Sciences GP, LLC2,459,703$46.3M14.13%00.0%Unchanged
Vanguard Group Inc2,442,551$45.9M0.00%+271,718+12.5%Added
Bain Capital Life Sciences Investors, LLC2,439,538$45.9M3.05%00.0%Unchanged
TCG Crossover Management, LLC2,117,103$39.8M1.96%−684,660−24.4%Reduced
Altshuler Shaham Ltd1,416,822$26.7M0.44%−1,977,619−58.3%Reduced
Omega Fund Management, LLC1,356,293$25.5M11.47%−680,000−33.4%Reduced
VR Adviser, LLC1,169,298$22.0M1.24%−1,126,021−49.1%Reduced
Wellington Management Group LLP1,125,395$21.2M0.00%−99,900−8.2%Reduced
State Street Corp1,114,581$21.0M0.00%+633,206+131.5%Added
Samsara BioCapital, LLC962,154$18.1M2.36%−481,077−33.3%Reduced
Marshall Wace, LLP867,999$16.3M0.02%+577,473+198.8%Added
Parkman Healthcare Partners LLC843,502$15.9M1.74%+127,998+17.9%Added
Geode Capital Management, LLC817,109$15.4M0.00%+170,474+26.4%Added
Siren, L.L.C.788,450$14.8M0.58%00.0%Unchanged
Woodline Partners LP602,252$11.3M0.05%+44,000+7.9%Added
Nantahala Capital Management, LLC594,971$11.2M0.69%00.0%Unchanged
Integral Health Asset Management, LLC575,000$10.8M0.79%+575,000New
Great Point Partners LLC300,000$5.64M2.36%00.0%Unchanged
Charles Schwab Investment Management Inc284,828$5.36M0.00%+106,575+59.8%Added
UBS Group AG272,271$5.12M0.00%+39,384+16.9%Added
Northern Trust Corp254,719$4.79M0.00%+25,416+11.1%Added
Goldman Sachs Group Inc223,214$4.20M0.00%+223,214New
Schonfeld Strategic Advisors LLC190,244$3.58M0.02%−175,546−48.0%Reduced
Ikarian Capital, LLC161,113$3.03M0.69%+161,113New
SummitTX Capital, L.P.112,404$2.11M0.09%+112,404New
Bank of New York Mellon Corp91,521$1.72M0.00%+11,755+14.7%Added
Morgan Stanley87,535$1.65M0.00%−11,773−11.9%Reduced
Barclays PLC85,315$1.60M0.00%−11,675−12.0%Reduced
Balyasny Asset Management LLC73,131$1.38M0.00%+73,131New
American Century Companies Inc71,540$1.35M0.00%+49,178+219.9%Added
Nuveen, LLC69,882$1.31M0.00%−4,054−5.5%Reduced
Boothbay Fund Management, LLC61,299$1.15M0.03%+61,299New
Bank of America Corp55,473$1.04M0.00%+37,442+207.7%Added
Exome Asset Management LLC51,960$977.4K0.65%+51,960New
Rhumbline Advisers49,406$929.3K0.00%+1,340+2.8%Added
Verition Fund Management LLC47,001$884.1K0.01%+13,496+40.3%Added
Citigroup Inc42,037$790.7K0.00%+30,342+259.4%Added
Millennium Management LLC40,113$754.5K0.00%+40,113New
Rafferty Asset Management, LLC34,521$649.3K0.00%+34,521New
AQR Capital Management LLC29,954$563.4K0.00%+202+0.7%Added
JPMorgan Chase & Co29,947$563.3K0.00%+13,478+81.8%Added
Nomura Holdings Inc28,290$532.1K0.00%+28,290New
Deutsche Bank AG26,737$502.9K0.00%+3,334+14.2%Added
Alps Advisors Inc25,962$488.3K0.00%−3,014−10.4%Reduced
Wells Fargo & Company25,160$473.3K0.00%+2,796+12.5%Added
MetLife Investment Management21,691$408.0K0.00%00.0%Unchanged
Alliancebernstein L.P.19,850$373.4K0.00%−4,710−19.2%Reduced
Price T Rowe Associates Inc18,501$349.0K0.00%+1,053+6.0%Added
Caption Management, LLC18,196$342.3K0.02%+18,196New
Invesco Ltd.17,190$323.3K0.00%+890+5.5%Added
Mirae Asset Global ETFs Holdings Ltd.16,863$314.6K0.00%−2,221−11.6%Reduced
Prelude Capital Management, LLC15,735$296.0K0.02%+15,735New
Commonwealth Equity Services, LLC15,503$292.0K0.00%−23−0.1%Reduced
Quantinno Capital Management LP14,889$280.1K0.00%+4,275+40.3%Added
Creative Planning14,266$268.3K0.00%+236+1.7%Added
Manufacturers Life Insurance Company, The12,092$227.5K0.00%−1,098−8.3%Reduced
Mariner, LLC10,933$205.7K0.00%+10,933New
Two Sigma Investments, LP10,500$197.5K0.00%+10,500New
Intech Investment Management LLC10,396$195.5K0.00%−10,894−51.2%Reduced
Virtus Investment Advisers, Inc.9,843$185.1K0.05%+1,709+21.0%Added
Police & Firemen's Retirement System of New Jersey9,447$177.7K0.00%+1,614+20.6%Added
BNP Paribas Arbitrage, SA6,527$122.8K0.00%+3,430+110.8%Added
New York State Common Retirement Fund6,300$118.5K0.00%+1,600+34.0%Added
CWM, LLC3,341$63.0K0.00%+29+0.9%Added
Russell Investments Group, Ltd.3,034$57.1K0.00%+2,887+1,963.9%Added
Legal & General Group Plc2,924$55.0K0.00%−250−7.9%Reduced
Ameritas Investment Partners, Inc.2,741$51.6K0.00%−817−23.0%Reduced
Sterling Capital Management LLC2,264$42.6K0.00%+1,323+140.6%Added
California State Teachers Retirement System2,176$40.9K0.00%+2+0.1%Added
Tower Research Capital LLC (TRC)1,868$35.1K0.00%−1,183−38.8%Reduced
Group One Trading, L.P.1,305$24.5K0.00%+1,305New
Aster Capital Management (DIFC) Ltd1,141$21.5K0.01%+1,141New
GAMMA Investing LLC890$16.7K0.00%+197+28.4%Added
Royal Bank of Canada832$16.0K0.00%−2,258−73.1%Reduced
Amalgamated Bank594$11.0K0.00%00.0%Unchanged
Versant Capital Management, Inc548$10.3K0.00%−10−1.8%Reduced
US Bancorp531$9.99K0.00%−128−19.4%Reduced
Global Retirement Partners, LLC332$6.25K0.00%+332New
EverSource Wealth Advisors, LLC310$5.83K0.00%+1+0.3%Added
Clearstead Advisors, LLC163$3.07K0.00%00.0%Unchanged
SRS Capital Advisors, Inc.149$2.80K0.00%+149New
The PNC Financial Services Group, Inc.130$2.45K0.00%+130New
J.Safra Asset Management Corp128$2.41K0.00%+128New
Essential Partners LLC97$1.82K0.00%00.0%Unchanged
Nisa Investment Advisors, LLC96$1.81K0.00%00.0%Unchanged
Allworth Financial LP67$1.26K0.00%+1+1.5%Added
N.E.W. Advisory Services LLC60$1.13K0.00%+60New
Signaturefd, LLC51$9590.00%+2+4.1%Added
Sunbelt Securities, Inc.19$3570.00%+19New
Parallel Advisors, LLC2$380.00%00.0%Unchanged
IFP Advisors, Inc2$380.00%+1+100.0%Added
Deep Track Capital, LP0$00.00%−1,442,767−100.0%Sold out
Lynx1 Capital Management LP0$00.00%−219,247−100.0%Sold out
Velan Capital Investment Management LP0$00.00%−107,000−100.0%Sold out
Alyeska Investment Group, L.P.0$00.00%−85,000−100.0%Sold out
Susquehanna International Group, LLP0$00.00%−42,263−100.0%Sold out