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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, Q1 2026

Institutional positions in Upstream Bio, Inc. as of Mar 31, 2026. 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
140
+10 vs. Q4 2025
Shares held
44.9M
−1.02M (−2.2%) vs. Q4 2025
Total value
$404.5M
−$841.8M (−67.5%) vs. Q4 2025
New holders
47
47 more added
Sold out
37
35 more reduced

3 institutions that held it in Q4 2025 haven't filed for Q1 2026 yet. Not filing isn't selling, so they aren't counted as sold out or in the changes above.

Compare with Q4 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 holdersQ1 2026: 140 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 heldQ1 2026: $404.5M
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, Q1 2026

Shares, value and share of portfolio for each institution holding Upstream Bio, Inc.; share changes are against Q4 2025.

Institutions holding UPB in Q1 2026
InstitutionSharesValue% of portfolioChange in sharesAction
Covestor Ltd4$00.00%+4New
IFP Advisors, Inc1$90.00%00.0%Unchanged
Freestone Grove Partners LP1$90.00%+1New
Parallel Advisors, LLC2$180.00%00.0%Unchanged
SJS Investment Consulting Inc.2$180.00%+2New
Root Financial Partners, LLC20$1800.00%+20New
Caitong International Asset Management Co., Ltd23$2070.00%+23New
Ameritas Advisory Services, LLC31$2790.00%+31New
Rothschild Investment LLC61$5490.00%+60+6,000.0%Added
Signaturefd, LLC66$5940.00%−51−43.6%Reduced
SRS Capital Advisors, Inc.77$6930.00%+75+3,750.0%Added
Farther Finance Advisors, LLC81$7540.00%+81New
Wealth Preservation Advisors, LLC86$7740.00%+86New
New York State Common Retirement Fund100$9000.00%−11,600−99.1%Reduced
N.E.W. Advisory Services LLC120$1.08K0.00%+60+100.0%Added
Natixis120$1.08K0.00%+120New
Torren Management, LLC162$1.46K0.00%−937−85.3%Reduced
MAI Capital Management171$1.54K0.00%+171New
EverSource Wealth Advisors, LLC222$2.00K0.00%−60−21.3%Reduced
Allworth Financial LP263$2.37K0.00%+195+286.8%Added
Advisor Group Holdings, Inc.389$3.50K0.00%+384+7,680.0%Added
Essential Partners LLC402$3.62K0.00%+305+314.4%Added
Zurcher Kantonalbank (Zurich Cantonalbank)477$4.29K0.00%+477New
UBS Asset Management Americas Inc588$5.29K0.00%+346+143.0%Added
US Bancorp590$5.31K0.00%+44+8.1%Added
Quantbot Technologies LP663$5.97K0.00%+663New
GAMMA Investing LLC715$6.43K0.00%−185−20.6%Reduced
Rockefeller Capital Management L.P.738$6.64K0.00%+738New
Versant Capital Management, Inc762$6.86K0.00%+204+36.6%Added
Sterling Capital Management LLC1,094$9.85K0.00%−825−43.0%Reduced
Larson Financial Group LLC1,107$9.96K0.00%+1,093+7,807.1%Added
GF Fund Management Co. Ltd.1,203$10.8K0.00%+142+13.4%Added
Tower Research Capital LLC (TRC)1,425$12.8K0.00%+756+113.0%Added
Ameritas Investment Partners, Inc.2,741$24.7K0.00%00.0%Unchanged
Mirae Asset Global Investments Co., Ltd.2,819$25.4K0.00%+193+7.3%Added
Wellington Grp LLC3,000$27.0K0.01%+1,000+50.0%Added
Russell Investments Group, Ltd.3,647$32.8K0.00%+824+29.2%Added
CWM, LLC3,883$34.9K0.00%+523+15.6%Added
Vanguard Investments Australia, Ltd.4,096$36.9K0.00%+4,096New
Citigroup Inc5,055$45.5K0.00%−1,894−27.3%Reduced
Persistent Asset Partners Ltd5,495$49.5K0.02%−3,412−38.3%Reduced
KLP Kapitalforvaltning AS5,900$53.1K0.00%+3,000+103.4%Added
Vanguard Asset Management, Ltd9,250$83.3K0.00%+9,250New
Police & Firemen's Retirement System of New Jersey9,456$85.1K0.00%00.0%Unchanged
China Universal Asset Management Co., Ltd.9,590$86.3K0.01%+784+8.9%Added
Legal & General Group Plc9,609$86.5K0.00%−4,100−29.9%Reduced
STRS Ohio9,800$88.2K0.00%00.0%Unchanged
Shay Capital LLC10,000$90.0K0.01%+10,000New
Virtus Investment Advisers, Inc.10,046$90.4K0.02%+245+2.5%Added
Creative Planning10,850$97.7K0.00%−899−7.7%Reduced
CI Private Wealth, LLC12,157$109.4K0.00%+12,157New
Vanguard Global Advisers, LLC13,059$117.5K0.00%+13,059New
Franklin Resources Inc14,589$131.3K0.00%+14,589New
Manufacturers Life Insurance Company, The15,338$138.0K0.00%+5,191+51.2%Added
Mirae Asset Global ETFs Holdings Ltd.15,608$140.5K0.00%−1,883−10.8%Reduced
Susquehanna International Group, LLP15,961$143.6K0.00%−39,880−71.4%Reduced
Wells Fargo & Company18,402$165.6K0.00%−18,392−50.0%Reduced
MetLife Investment Management19,380$174.4K0.00%−298−1.5%Reduced
Nisa Investment Advisors, LLC19,558$176.0K0.00%+19,158+4,789.5%Added
Man Group plc21,154$190.4K0.00%+21,154New
Diadema Partners LP21,609$194.5K0.08%+1,109+5.4%Added
Entropy Technologies, LP23,336$210.0K0.01%+23,336New
DnB Asset Management AS23,515$211.6K0.00%+10,722+83.8%Added
Barclays PLC24,720$222.5K0.00%−499,779−95.3%Reduced
Victory Capital Management Inc25,866$232.8K0.00%+25,866New
Martingale Asset Management L P26,223$236.0K0.01%+26,223New
Tudor Investment Corp Et Al26,412$237.7K0.00%+26,412New
Price T Rowe Associates Inc26,434$238.0K0.00%+6,798+34.6%Added
Mariner, LLC27,314$245.8K0.00%+15,484+130.9%Added
Axq Capital, LP27,503$247.5K0.03%+27,503New
Bleakley Financial Group, LLC28,864$259.8K0.00%+28,864New
Aquatic Capital Management LLC31,484$283.4K0.01%+31,484New
Stonepine Capital Management, LLC35,000$315.0K0.28%+35,000New
ADAR1 Capital Management, LLC35,000$315.0K0.02%+35,000New
Gsa Capital Partners LLP39,232$353.0K0.02%+39,232New
California State Teachers Retirement System39,661$356.9K0.00%+25,009+170.7%Added
Invesco Ltd.40,510$364.6K0.00%−122,676−75.2%Reduced
Rhumbline Advisers41,203$370.8K0.00%−320−0.8%Reduced
State of Wisconsin Investment Board41,671$375.0K0.00%+41,671New
Alps Advisors Inc43,992$395.9K0.00%−384−0.9%Reduced
Squarepoint Ops LLC44,626$401.6K0.00%+44,626New
Swiss National Bank48,100$432.9K0.00%+21,500+80.8%Added
Bank of America Corp48,460$436.1K0.00%−37,924−43.9%Reduced
Quantinno Capital Management LP49,389$444.5K0.00%+33,974+220.4%Added
Renaissance Technologies LLC62,100$558.9K0.00%+45,700+278.7%Added
Marshall Wace, LLP66,770$600.9K0.00%−277,021−80.6%Reduced
AQR Capital Management LLC72,171$649.5K0.00%+41,668+136.6%Added
EntryPoint Capital, LLC73,568$662.1K0.19%+73,568New
Nuveen, LLC75,536$679.8K0.00%−3,032−3.9%Reduced
Simplify Asset Management Inc.77,793$700.1K0.01%+77,793New
Dimensional Fund Advisors LP80,002$719.5K0.00%+80,002New
Bank of New York Mellon Corp81,383$732.4K0.00%−3,470−4.1%Reduced
American Century Companies Inc87,624$788.6K0.00%−132−0.2%Reduced
ExodusPoint Capital Management, LP91,431$822.9K0.01%+16,029+21.3%Added
Alliancebernstein L.P.31,010$841.9K0.00%00.0%Unchanged
BNP Paribas Arbitrage, SA126,000$1.13M0.00%+121,024+2,432.2%Added
Boxer Capital Management, LLC150,000$1.35M0.18%00.0%Unchanged
Schonfeld Strategic Advisors LLC161,349$1.45M0.01%+45,542+39.3%Added
Trexquant Investment LP176,657$1.59M0.01%+145,608+469.0%Added
Point72 Asset Management, L.P.178,168$1.60M0.00%+178,168New