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Equibles

UPB

Upstream Bio, Inc.

Company with tickers: UPB

CIK
2022626
CUSIP
91678A107
Shares Outstanding
54,419,986
13F Activity (30d)
84 filings 78 filers

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 143
Total Value: $405,340,326
Total Shares: 45,037,814
Showing 1–100 of 147 holdings by value · page 1 of 2

Institutional Ownership Trend

6 quarters

Holder Concentration

Across 143 13F filers · Δ vs Dec 31, 2025
Top Holder
18.0%
Dec 2024 → Mar 2026 · range 14.7% – 18.0%
+3.3 pts
Top 5
49.6%
Dec 2024 → Mar 2026 · range 44.1% – 50.9%
+5.6 pts
Top 10
62.4%
Dec 2024 → Mar 2026 · range 62.4% – 75.7%
−0.3 pts
HHI
684
Dec 2024 → Mar 2026 · range 577 – 779
Broadly held+106

Quarterly Activity

vs Dec 31, 2025
New
47
Increased
49
Decreased
35
Sold Out
39
Unchanged
12
Holder count: +8
Institutional value: -70.9%
Shares held: -12.1%

Top Buyers

vs Dec 31, 2025
Institution Added Now Holds Open
Large FEDERATED HERMES, INC. +979,276 979,758
Mid Y-Intercept (Hong Kong) Ltd +954,072 1,000,631
Mega D. E. Shaw & Co., Inc. +793,389 820,480
Mega FMR LLC +583,361 8,101,563
Mega MORGAN STANLEY +430,541 552,609

Top Sellers

vs Dec 31, 2025
Institution Sold Now Holds Open
Mega UBS Group AG −1,574,989 231,254
Mid Altshuler Shaham Ltd −961,479 380,061
Mega STATE STREET CORP −613,876 705,350
Mid TCG Crossover Management, LLC −562,823 181,063
Mega WELLINGTON MANAGEMENT GROUP LLP −552,380 342,353

Top New Positions

vs Dec 31, 2025
Institution Acquired Value (USD) Open
Mega VANGUARD CAPITAL MANAGEMENT LLC 1,873,574 $16,862,166
Large SEB Asset Management AB 878,473 $7,906,257
Mega VANGUARD PORTFOLIO MANAGEMENT LLC 727,711 $6,549,399
Mega HSBC HOLDINGS PLC 640,326 $5,762,934
Large Qube Research & Technologies Ltd 619,321 $5,573,889

Top Sold-Out Positions

vs Dec 31, 2025
Institution Previously Held Last Value (USD) Open
Mega NORGES BANK 2,882,647 $78,263,866
Mega VANGUARD GROUP INC 2,388,439 $64,846,117
Mega JANUS HENDERSON GROUP PLC 1,527,958 $41,484,059
Small Omega Fund Management, LLC 1,326,293 $36,008,854
Mid Venrock Adviser, LLC 1,169,298 $31,746,440
Filter: New 47 Increased 49 Reduced 35 Sold out 39 Unchanged 12
Showing 100 of 147
All Common Calls Puts
Export CSV
Holder Value (USD) % of 13F Shares Open
Mega FMR LLC $72,914,067 17.99% 8,101,563
Mid ORBIMED ADVISORS LLC $51,242,301 12.64% 5,693,589
Mega BlackRock, Inc. $30,336,201 7.48% 3,370,689
Small Decheng Capital LLC $24,523,812 6.05% 2,724,868
Small ENAVATE SCIENCES GP, LLC $22,137,327 5.46% 2,459,703
Mega VANGUARD CAPITAL MANAGEMENT LLC $16,862,166 4.16% 1,873,574
Mid Y-Intercept (Hong Kong) Ltd $9,005,679 2.22% 1,000,631
Large FEDERATED HERMES, INC. $8,817,822 2.18% 979,758
Mega GEODE CAPITAL MANAGEMENT, LLC $8,555,553 2.11% 950,617
Mega MILLENNIUM MANAGEMENT LLC $8,435,907 2.08% 937,323
Large SEB Asset Management AB $7,906,257 1.95% 878,473
Mid Bain Capital Life Sciences Investors, LLC $7,804,899 1.93% 867,211
Large Woodline Partners LP $7,483,329 1.85% 831,481
Mega D. E. Shaw & Co., Inc. $7,384,320 1.82% 820,480
Small Parkman Healthcare Partners LLC $7,081,047 1.75% 786,783
Mid SAMSARA BIOCAPITAL, LLC $6,624,423 1.63% 736,047
Large Pictet Asset Management Holding SA $6,600,879 1.63% 733,431
Mega VANGUARD PORTFOLIO MANAGEMENT LLC $6,549,399 1.62% 727,711
Mega STATE STREET CORP $6,348,150 1.57% 705,350
Mega HSBC HOLDINGS PLC $5,762,934 1.42% 640,326
Large Qube Research & Technologies Ltd $5,573,889 1.38% 619,321
Mega MORGAN STANLEY $4,973,481 1.23% 552,609
Mega JPMORGAN CHASE & CO $4,167,009 1.03% 463,001
Mid Nantahala Capital Management, LLC $3,600,000 0.89% 400,000
Mid Altshuler Shaham Ltd $3,420,549 0.84% 380,061
Small SPHERA FUNDS MANAGEMENT LTD. $3,222,000 0.79% 358,000
Mega WELLINGTON MANAGEMENT GROUP LLP $3,081,177 0.76% 342,353
Small Propel Bio Management, LLC $3,076,011 0.76% 341,779
Mid Jump Financial, LLC $2,874,600 0.71% 319,400
Mega GOLDMAN SACHS GROUP INC $2,849,283 0.70% 316,587
Large Alyeska Investment Group, L.P. $2,684,961 0.66% 298,329
Mega NORTHERN TRUST CORP Bank $2,348,928 0.58% 260,992
Mega CHARLES SCHWAB INVESTMENT MANAGEMENT INC $2,319,561 0.57% 257,729
Small Prosight Management, LP $2,170,107 0.54% 241,123
Mega UBS Group AG $2,081,286 0.51% 231,254
Mega VANGUARD FIDUCIARY TRUST CO Bank $2,017,413 0.50% 224,157
Mid XTX Topco Ltd $1,883,493 0.46% 209,277
Mega ARROWSTREET CAPITAL, LIMITED PARTNERSHIP $1,665,783 0.41% 185,087
Mid TCG Crossover Management, LLC $1,629,567 0.40% 181,063
Mega DEUTSCHE BANK AG\ Bank $1,628,001 0.40% 180,889
Large Point72 Asset Management, L.P. $1,603,512 0.40% 178,168
Large Trexquant Investment LP $1,589,913 0.39% 176,657
Large Schonfeld Strategic Advisors LLC $1,452,141 0.36% 161,349
Small Boxer Capital Management, LLC $1,350,000 0.33% 150,000
Mega BNP PARIBAS ARBITRAGE, SA $1,134,000 0.28% 126,000
Large ExodusPoint Capital Management, LP $822,879 0.20% 91,431
Mega AMERICAN CENTURY COMPANIES INC $788,616 0.19% 87,624
Mega Bank of New York Mellon Corp Bank $732,447 0.18% 81,383
Mega DIMENSIONAL FUND ADVISORS LP $720,018 0.18% 80,002
Small Simplify Asset Management Inc. $700,137 0.17% 77,793
Mega Nuveen, LLC $679,824 0.17% 75,536
Small EntryPoint Capital, LLC $662,112 0.16% 73,568
Mega AQR CAPITAL MANAGEMENT LLC $649,539 0.16% 72,171
Large MARSHALL WACE, LLP $600,930 0.15% 66,770
Large RENAISSANCE TECHNOLOGIES LLC $558,900 0.14% 62,100
Mega CITADEL ADVISORS LLC $483,300 0.12% 53,700
Large Quantinno Capital Management LP $444,501 0.11% 49,389
Mega BANK OF AMERICA CORP /DE/ Bank $436,140 0.11% 48,460
Mega Swiss National Bank Bank $432,900 0.11% 48,100
Large Squarepoint Ops LLC $401,634 0.10% 44,626
Large ALPS ADVISORS INC $395,928 0.10% 43,992
Large STATE OF WISCONSIN INVESTMENT BOARD $375,039 0.09% 41,671
Mega RHUMBLINE ADVISERS $370,827 0.09% 41,203
Mega Invesco Ltd. $364,590 0.09% 40,510
Large CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM Pension $356,949 0.09% 39,661
Mid GSA CAPITAL PARTNERS LLP $353,088 0.09% 39,232
Mid ADAR1 Capital Management, LLC $315,000 0.08% 35,000
Small Stonepine Capital Management, LLC $315,000 0.08% 35,000
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP $305,100 0.08% 33,900
Mid Aquatic Capital Management LLC $283,356 0.07% 31,484
Mega ALLIANCEBERNSTEIN L.P. $279,090 0.07% 31,010
Mid Bleakley Financial Group, LLC $259,776 0.06% 28,864
Small AXQ CAPITAL, LP $247,527 0.06% 27,503
Large Mariner, LLC $245,826 0.06% 27,314
Mega PRICE T ROWE ASSOCIATES INC /MD/ $237,906 0.06% 26,434
Large TUDOR INVESTMENT CORP ET AL $237,708 0.06% 26,412
Mid MARTINGALE ASSET MANAGEMENT L P $236,007 0.06% 26,223
Mega VICTORY CAPITAL MANAGEMENT INC $232,794 0.06% 25,866
Mega CITADEL ADVISORS LLC $223,200 0.06% 24,800
Mega BARCLAYS PLC $222,480 0.05% 24,720
Large DNB Asset Management AS $211,635 0.05% 23,515
Mid Entropy Technologies, LP $210,024 0.05% 23,336
Small DIADEMA PARTNERS LP $194,481 0.05% 21,609
Large Man Group plc $190,386 0.05% 21,154
Large NISA INVESTMENT ADVISORS, LLC $176,022 0.04% 19,558
Large MetLife Investment Management, LLC $174,420 0.04% 19,380
Mega WELLS FARGO & COMPANY/MN $165,618 0.04% 18,402
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP $143,649 0.04% 15,961
Large MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. Mutual Fund $140,472 0.03% 15,608
Mega MANUFACTURERS LIFE INSURANCE COMPANY, THE Insurance $138,042 0.03% 15,338
Mega JANE STREET GROUP, LLC $137,700 0.03% 15,300
Mega FRANKLIN RESOURCES INC $131,301 0.03% 14,589
Mega Vanguard Global Advisers, LLC $117,531 0.03% 13,059
Large Corient Private Wealth LLC $109,413 0.03% 12,157
Mega SUSQUEHANNA INTERNATIONAL GROUP, LLP $108,900 0.03% 12,100
Large Point72 Asset Management, L.P. $103,500 0.03% 11,500
Large Creative Planning $97,650 0.02% 10,850
Small Virtus Investment Advisers, LLC $90,414 0.02% 10,046
Mid Shay Capital LLC $90,000 0.02% 10,000
Large STRS OHIO $88,200 0.02% 9,800

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