13F

Stock

Upstream Bio, Inc.

UPB · held by 141 managers

Reported value

$403.9M

Holders

141

+40 new · −37 exited

Holders’ est. mark

−$580.7M

Price effect on 93 books still in the name

Largest holder

$72.9M

Fidelity

Notable conviction

Share of each notable manager’s 13F book.

Holder count by quarter

Who holds it

Notable only
InvestorSharesValueEst. markChange
Fidelity8.1M$72.9M−$136.5MCut−$131.2M
ORBIMED ADVISORS LLC5.69M$51.2M−$103.3MCut−$103.3M
BlackRock, Inc.3.37M$30.3M−$60.7MCut−$60.5M
Decheng Capital LLC2.72M$24.5M−$49.5MCut−$60.8M
ENAVATE SCIENCES GP, LLC2.46M$22.1M−$44.6MCut−$44.6M
VANGUARD CAPITAL MANAGEMENT LLC1.87M$16.9MHeld
Y-Intercept (Hong Kong) Ltd1M$9.01M−$845KAdded$7.74M
FEDERATED HERMES, INC.979.8K$8.82M−$8.75KAdded$8.8M
GEODE CAPITAL MANAGEMENT, LLC950.6K$8.56M−$15.5MCut−$14.6M
MILLENNIUM MANAGEMENT LLC937.3K$8.44M−$9.39MCut−$5.61M
SEB Asset Management AB878.5K$7.91MHeld
Bain Capital Life Sciences Investors, LLC867.2K$7.8M−$15.7MCut−$28.3M
Woodline Partners LP831.5K$7.48M−$13.8MCut−$13.2M
D. E. Shaw & Co., Inc.820.5K$7.38M−$491.7KAdded$6.65M
Parkman Healthcare Partners LLC786.8K$7.08M−$14.3MCut−$15.6M
SAMSARA BIOCAPITAL, LLC736K$6.62M−$13.4MCut−$13.4M
Pictet Asset Management Holding SA733.4K$6.6M−$13.3MCut−$14.4M
VANGUARD PORTFOLIO MANAGEMENT LLC727.7K$6.55MHeld
State Street705.4K$6.35M−$12.8MCut−$29.5M
HSBC HOLDINGS PLC640.3K$5.76MNew
Qube Research & Technologies Ltd619.3K$5.57MNew
MORGAN STANLEY552.6K$4.97M−$2.22MAdded$1.66M
JPMORGAN CHASE & CO463K$4.07M−$2.03MAdded$1.07M
Nantahala Capital Management, LLC400K$3.6M−$7.26MCut−$9.84M
Altshuler Shaham Ltd380.1K$3.42M−$6.9MCut−$33M
SPHERA FUNDS MANAGEMENT LTD.358K$3.22MNew
Propel Bio Management, LLC341.8K$3.1MNew
WELLINGTON MANAGEMENT GROUP LLP342.4K$3.08M−$6.21MCut−$21.2M
Jump Financial, LLC319.4K$2.87MNew
GOLDMAN SACHS GROUP INC316.6K$2.85M−$5.75MCut−$6.2M
Alyeska Investment Group, L.P.298.3K$2.68M−$5.41MCut−$5.41M
NORTHERN TRUST CORP261K$2.35M−$4.3MCut−$4.08M
CHARLES SCHWAB INVESTMENT MANAGEMENT INC257.7K$2.32M−$4.68MCut−$5.42M
Prosight Management, LP241.1K$2.17MNew
UBS Group AG231.3K$2.08M−$4.2MCut−$47M
VANGUARD FIDUCIARY TRUST CO224.2K$2.02MHeld
XTX Topco Ltd209.3K$1.88M−$273.9KAdded$1.47M
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP185.1K$1.67MNew
TCG Crossover Management, LLC181.1K$1.63M−$3.29MCut−$18.6M
DEUTSCHE BANK AG\180.9K$1.63M−$2.32MCut−$1.84M
Point72 Asset Management, L.P.178.2K$1.6MNew
Trexquant Investment LP176.7K$1.59M−$563.5KAdded$746.9K
Schonfeld Strategic Advisors LLC161.3K$1.45M−$2.1MCut−$1.69M
Boxer Capital Management, LLC150K$1.35M−$2.72MCut−$2.72M
BNP PARIBAS FINANCIAL MARKETS126K$1.13M−$90.3KAdded$998.9K
ALLIANCEBERNSTEIN L.P.31K$841.9K$0Held
ExodusPoint Capital Management, LP91.4K$822.9K−$1.37MCut−$1.22M
AMERICAN CENTURY COMPANIES INC87.6K$788.6K−$1.59MCut−$1.59M
Bank of New York Mellon Corp81.4K$732.4K−$1.48MCut−$1.57M
DIMENSIONAL FUND ADVISORS LP80K$719.5KNew
Simplify Asset Management Inc.77.8K$700.1KNew
Nuveen, LLC75.5K$679.8K−$1.37MCut−$1.45M
EntryPoint Capital, LLC73.6K$662.1KNew
Icahn Capital72.2K$649.5K−$553.6KCut−$178.6K
MARSHALL WACE, LLP66.8K$600.9K−$1.21MCut−$8.73M
Renaissance Technologies62.1K$558.9K−$297.7KAdded$113.6K
Quantinno Capital Management LP49.4K$444.5K−$279.8KAdded$26K
BANK OF AMERICA CORP /DE/48.5K$436.1K−$879.5KCut−$1.91M
Swiss National Bank48.1K$432.9K−$482.8KCut−$289.3K
Squarepoint Ops LLC44.6K$401.6KNew
ALPS ADVISORS INC44K$395.9K−$798.5KCut−$808.9K
STATE OF WISCONSIN INVESTMENT BOARD41.7K$375KNew
RHUMBLINE ADVISERS41.2K$370.8K−$747.8KCut−$756.5K
Invesco Ltd.40.5K$364.6K−$735.3KCut−$4.07M
CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM39.7K$356.9K−$265.9KCut−$40.9K
ADAR1 Capital Management, LLC35K$315KNew
Stonepine Capital Management, LLC35K$315KNew
Aquatic Capital Management LLC31.5K$283.4KNew
Bleakley Financial Group, LLC28.9K$259.8KNew
AXQ CAPITAL, LP27.5K$247.5KNew
Mariner, LLC27.3K$245.8K−$214.7KCut−$75.3K
TUDOR INVESTMENT CORP ET AL26.4K$237.7KNew
MARTINGALE ASSET MANAGEMENT L P26.2K$236KNew
VICTORY CAPITAL MANAGEMENT INC25.9K$232.8KNew
BARCLAYS PLC24.7K$222.5K−$448.7KCut−$14M
DNB Asset Management AS23.5K$211.6K−$232.2KCut−$135.7K
Entropy Technologies, LP23.3K$210KNew
DIADEMA PARTNERS LP21.6K$194.5K−$372.1KCut−$362.1K
Man Group plc21.2K$190.4KNew
NISA INVESTMENT ADVISORS, LLC19.6K$176K−$7.26KAdded$165.2K
MetLife Investment Management, LLC19.4K$174.4K−$351.7KCut−$359.8K
WELLS FARGO & COMPANY/MN18.4K$165.6K−$334KCut−$833.3K
SUSQUEHANNA INTERNATIONAL GROUP, LLP16K$143.6K−$289.7KCut−$1.37M
MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd.15.6K$140.5K−$283.6KCut−$334.8K
MANUFACTURERS LIFE INSURANCE COMPANY, THE15.3K$138K−$184.2KCut−$137.4K
FRANKLIN RESOURCES INC14.6K$131.3KNew
Vanguard Global Advisers, LLC13.1K$117.5KHeld
Corient Private Wealth LLC12.2K$109.4KNew
Creative Planning10.8K$97.7K−$196.9KCut−$221.3K
Virtus Investment Advisers, LLC10K$90.4K−$177.9KCut−$175.7K
Shay Capital LLC10K$90KNew
STRS OHIO9.8K$88.2K−$177.9KCut−$177.9K
Legal & General Group Plc9.61K$86.5K−$174.4KCut−$285.7K
China Universal Asset Management Co., Ltd.9.59K$86.3K−$159.8KCut−$152.8K
Police & Firemen's Retirement System of New Jersey9.46K$85.1K−$171.6KCut−$171.6K
VANGUARD ASSET MANAGEMENT, Ltd9.25K$83.3KHeld
KLP KAPITALFORVALTNING AS5.9K$53.1K−$52.6KCut−$25.6K
Persistent Asset Partners Ltd5.5K$49.5K−$99.7KCut−$192.4K
CITIGROUP INC5.05K$45.5K−$91.7KCut−$143.2K
Vanguard Investments Australia, Ltd.4.1K$36.9KHeld
CWM, LLC3.88K$34.9K$30.1KAdded$34.9K
Russell Investments Group, Ltd.3.65K$32.8K−$51.2KCut−$43.8K
Wellington Grp LLC3K$27K−$36.3KCut−$27.3K
Mirae Asset Global Investments Co., Ltd.2.82K$25.4K−$47.7KCut−$45.9K
Ameritas Investment Partners, Inc.2.74K$24.7K−$49.7KCut−$49.7K
Tower Research Capital LLC (TRC)1.43K$12.8K−$12.1KCut−$5.34K
GF FUND MANAGEMENT CO. LTD.1.2K$10.8K−$19.3KCut−$18K
Larson Financial Group LLC1.11K$9.96K−$254Added$9.58K
Sterling Capital Management LLC1.09K$9.85K−$19.9KCut−$42.3K
Versant Capital Management, Inc762$6.86K−$10.1KCut−$8.29K
Rockefeller Capital Management L.P.738$6.64KNew
GAMMA Investing LLC715$6.43K−$13KCut−$18K
Quantbot Technologies LP663$5.97KNew
US BANCORP \DE\590$5.31K−$9.91KCut−$9.51K
UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC588$5.29K−$4.39KCut−$1.28K
Zurcher Kantonalbank (Zurich Cantonalbank)477$4.29KNew
Essential Partners LLC402$3.62K−$1.76KAdded$984
OSAIC HOLDINGS, INC.389$3.5K−$91Added$3.37K
Allworth Financial LP263$2.37K−$1.24KAdded$520
EverSource Wealth Advisors, LLC222$2K−$4.03KCut−$5.66K
MAI Capital Management171$1.54KNew
Torren Management, LLC162$1.46K−$2.94KCut−$28.4K
NATIXIS120$1.08KNew
N.E.W. Advisory Services LLC120$1.08K−$1.09KCut−$549
NEW YORK STATE COMMON RETIREMENT FUND100$900−$1.81KCut−$316.8K
Wealth Preservation Advisors, LLC86$774New
Farther Finance Advisors, LLC81$754New
Arax Advisory Partners77$693−$36Added$639
SIGNATUREFD, LLC66$594−$1.2KCut−$2.58K
ROTHSCHILD INVESTMENT LLC61$549−$18Added$522
GSA CAPITAL PARTNERS LLP39.2K$353New
Ameritas Advisory Services, LLC31$279New
PRICE T ROWE ASSOCIATES INC /MD/26.4K$238−$357Cut−$296
Caitong International Asset Management Co., Ltd23$207New
Root Financial Partners, LLC20$180New
SJS Investment Consulting Inc.2$18New
Parallel Advisors, LLC2$18−$36Cut−$36
IFP Advisors, Inc1$9−$18Cut−$18
Freestone Grove Partners LP1$9New
NOMURA ASSET MANAGEMENT CO LTD0$0Held
Covestor Ltd4$0New

Who left

Positions as of Q1 2026. 13F filings arrive up to 45 days after quarter-end and omit shorts. Values are quarter-end marks, as filed. Estimated mark is the price effect on shares still held — not realized P&L or investment advice.