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Institutional Ownership · SEC Form 13F

Who owns JBIO (JBIO)


Which tracked institutional funds hold JBIO, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See JBIO company fundamentals →

Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.

120
Institutional holders
49,709,073
Shares held (tracked funds)

How the tape is positioned

20 tracked funds added or opened JBIO while 37 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.

A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.

Conviction spread

JBIO’s largest tracked holder by dollar value, FMR LLC, sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.

Book-share is each fund’s reported value in JBIO divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.

Institutional & insider positioning

Between 2025-Q4 and 2026-Q1, across 120 tracked filers holding JBIO, 67 increased or opened the position and 47 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.

This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.

New buyers & exits

Funds opening or closing a position in JBIO between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.

New buyers 9

  • JANUS HENDERSON GROUP PLC$44M
  • VANGUARD CAPITAL MANAGEMENT LLC$25M
  • ACORN CAPITAL ADVISORS, LLC$11M
  • BALYASNY ASSET MANAGEMENT L.P.$6M
  • Foresite Capital Management VI LLC$4M
  • VANGUARD FIDUCIARY TRUST CO$3M

Full exits 5

  • VANGUARD GROUP INC$30M
  • Caption Management, LLC$5M
  • AMERIPRISE FINANCIAL INC$3M
  • Woodline Partners LP$1M
  • 9823 Capital, L.P.$821K

Largest adds

  • Avidity Partners Management LP$13M
  • Ikarian Capital, LLC$3M
  • Russell Investments Group, Ltd.$1M
  • CITADEL ADVISORS LLC$1M
  • Connor, Clark & Lunn Investment Management Ltd.$1M
  • MILLENNIUM MANAGEMENT LLC$1M

Largest trims

  • RTW INVESTMENTS, LP$14M
  • BlackRock, Inc.$12M
  • FMR LLC$9M
  • Fairmount Funds Management LLC$6M
  • ORBIMED ADVISORS LLC$6M
  • RA CAPITAL MANAGEMENT, L.P.$5M

Institutional holders

One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).

FundSharesReported value% of valueQuarter
FMR LLC added6,952,133$98M12.1%2026-Q1
Fairmount Funds Management LLC4,553,494$64M7.9%2026-Q1
RA CAPITAL MANAGEMENT, L.P.3,671,083$52M6.4%2026-Q1
Bellevue Group AG added3,501,502$49M6.1%2026-Q1
Venrock Adviser, LLC3,220,364$45M5.6%2026-Q1
JANUS HENDERSON GROUP PLC new3,105,669$44M5.4%2026-Q1
Avidity Partners Management LP1,400,708$34M4.2%2026-Q1
BlackRock, Inc. trimmed2,313,949$33M4.0%2026-Q1
VANGUARD CAPITAL MANAGEMENT LLC new1,796,652$25M3.1%2026-Q1
BAKER BROS. ADVISORS LP1,641,137$23M2.9%2026-Q1
Remedium Capital Partners, LLC1,577,750$22M2.7%2026-Q1
Versant Venture Management, LLC1,525,820$21M2.7%2026-Q1
SAMSARA BIOCAPITAL, LLC968,798$14M1.7%2026-Q1
GREAT POINT PARTNERS LLC added964,462$14M1.7%2026-Q1
MARSHALL WACE, LLP added940,504$13M1.6%2026-Q1
Aberdeen Group plc867,284$12M1.5%2026-Q1
GEODE CAPITAL MANAGEMENT, LLC trimmed822,520$12M1.4%2026-Q1
Soleus Capital Management, L.P.796,744$11M1.4%2026-Q1
ACORN CAPITAL ADVISORS, LLC new786,760$11M1.4%2026-Q1
STATE STREET CORP added655,690$9M1.1%2026-Q1
Affinity Asset Advisors, LLC trimmed639,956$9M1.1%2026-Q1
Driehaus Capital Management LLC trimmed635,498$9M1.1%2026-Q1
RTW INVESTMENTS, LP trimmed573,205$8M1.0%2026-Q1
Ikarian Capital, LLC added512,349$7M0.9%2026-Q1
Opaleye Management Inc.427,608$6M0.7%2026-Q1
BALYASNY ASSET MANAGEMENT L.P. added402,489$6M0.7%2026-Q1
Logos Global Management LP added400,000$6M0.7%2026-Q1
Foresite Capital Management VI LLC new320,000$4M0.6%2026-Q1
Point72 Asset Management, L.P. trimmed264,315$4M0.5%2026-Q1
NORTHERN TRUST CORP trimmed241,905$3M0.4%2026-Q1
VANGUARD FIDUCIARY TRUST CO new219,497$3M0.4%2026-Q1
VANGUARD PORTFOLIO MANAGEMENT LLC new211,319$3M0.4%2026-Q1
ORBIMED ADVISORS LLC trimmed185,011$3M0.3%2026-Q1
Connor, Clark & Lunn Investment Management Ltd. added169,051$2M0.3%2026-Q1
MILLENNIUM MANAGEMENT LLC added160,051$2M0.3%2026-Q1
STEMPOINT CAPITAL LP new154,034$2M0.3%2026-Q1
GOLDMAN SACHS GROUP INC added153,037$2M0.3%2026-Q1
BOOTHBAY FUND MANAGEMENT, LLC added139,968$2M0.2%2026-Q1
CITADEL ADVISORS LLC added137,222$2M0.2%2026-Q1
RENAISSANCE TECHNOLOGIES LLC added135,039$2M0.2%2026-Q1
WELLINGTON MANAGEMENT GROUP LLP added129,166$2M0.2%2026-Q1
Russell Investments Group, Ltd. added107,596$2M0.2%2026-Q1
Sofinnova Investments, Inc.107,391$2M0.2%2026-Q1
CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed91,647$1M0.2%2026-Q1
Bank of New York Mellon Corp trimmed89,964$1M0.2%2026-Q1
XTX Topco Ltd added78,108$1M0.1%2026-Q1
UBS Group AG trimmed65,022$914K0.1%2026-Q1
MORGAN STANLEY trimmed50,595$711K0.1%2026-Q1
ALLIANCEBERNSTEIN L.P.45,334$700K0.1%2026-Q1
Nuveen, LLC trimmed46,236$650K0.1%2026-Q1
Squarepoint Ops LLC added44,650$627K0.1%2026-Q1
RHUMBLINE ADVISERS trimmed40,551$570K0.1%2026-Q1
DEUTSCHE BANK AG\ added39,199$551K0.1%2026-Q1
BANK OF AMERICA CORP /DE/ added38,598$542K0.1%2026-Q1
SCHRODER INVESTMENT MANAGEMENT GROUP39,279$521K0.1%2026-Q1
AMERICAN CENTURY COMPANIES INC added33,369$469K0.1%2026-Q1
Quantinno Capital Management LP added30,551$429K0.1%2026-Q1
Invesco Ltd. trimmed29,560$415K0.1%2026-Q1
BNP PARIBAS FINANCIAL MARKETS added28,624$402K0.0%2026-Q1
Trexquant Investment LP new28,107$395K0.0%2026-Q1
Y-Intercept (Hong Kong) Ltd new25,131$353K0.0%2026-Q1
Qube Research & Technologies Ltd added24,792$348K0.0%2026-Q1
BARCLAYS PLC trimmed24,660$346K0.0%2026-Q1
HRT FINANCIAL LP added24,422$343K0.0%2026-Q1
Vanguard Global Advisers, LLC new23,698$333K0.0%2026-Q1
PRICE T ROWE ASSOCIATES INC /MD/ trimmed22,578$318K0.0%2026-Q1
ADAR1 Capital Management, LLC trimmed20,000$281K0.0%2026-Q1
GSA CAPITAL PARTNERS LLP trimmed19,555$275K0.0%2026-Q1
SUSQUEHANNA INTERNATIONAL GROUP, LLP added18,308$257K0.0%2026-Q1
TWO SIGMA INVESTMENTS, LP added18,251$256K0.0%2026-Q1
Virtus Investment Advisers, LLC added18,203$256K0.0%2026-Q1
MetLife Investment Management, LLC trimmed17,935$252K0.0%2026-Q1
DELTEC ASSET MANAGEMENT LLC15,756$221K0.0%2026-Q1
STATE OF WISCONSIN INVESTMENT BOARD trimmed15,021$211K0.0%2026-Q1
JPMORGAN CHASE & CO trimmed15,863$210K0.0%2026-Q1
MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. trimmed14,961$210K0.0%2026-Q1
ExodusPoint Capital Management, LP trimmed14,131$199K0.0%2026-Q1
WELLS FARGO & COMPANY/MN trimmed12,046$169K0.0%2026-Q1
VANGUARD GROUP INC added1,925,642$30M3.7%2025-Q4 stale
Deep Track Capital, LP trimmed2,279,892$20M2.4%2025-Q3 stale
Frazier Life Sciences Management, L.P. trimmed1,413,280$12M1.5%2025-Q3 stale
Caption Management, LLC added297,095$5M0.6%2025-Q4 stale
DEERFIELD MANAGEMENT COMPANY, L.P.531,163$5M0.6%2025-Q3 stale
Atlas Venture Life Science Advisors, LLC1,799,232$5M0.6%2025-Q1 stale
BRAIDWELL LP1,440,499$4M0.4%2025-Q1 stale
Allostery Investments LP added1,421,568$4M0.4%2025-Q1 stale
AMERIPRISE FINANCIAL INC new187,254$3M0.4%2025-Q4 stale
Blackstone Inc. added955,125$2M0.3%2025-Q1 stale
Jefferies Financial Group Inc.600,000$2M0.2%2025-Q1 stale
Cable Car Capital, LP new589,780$1M0.2%2025-Q1 stale
Woodline Partners LP trimmed82,056$1M0.2%2025-Q4 stale
9823 Capital, L.P. new53,191$821K0.1%2025-Q4 stale
TWO SIGMA ADVISERS, LP added291,800$732K0.1%2025-Q1 stale
TCG Crossover Management, LLC trimmed64,023$640K0.1%2025-Q2 stale
TUDOR INVESTMENT CORP ET AL new24,200$373K0.0%2025-Q4 stale
MANUFACTURERS LIFE INSURANCE COMPANY, THE added14,012$216K0.0%2025-Q4 stale
LOS ANGELES CAPITAL MANAGEMENT LLC new21,570$212K0.0%2025-Q4 stale
Persistent Asset Partners Ltd new12,469$192K0.0%2025-Q4 stale
INTECH INVESTMENT MANAGEMENT LLC trimmed11,802$182K0.0%2025-Q4 stale
TANG CAPITAL MANAGEMENT LLC new69,754$175K0.0%2025-Q1 stale

Ownership over time

Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.

HoldersTotal shares

Reading this table

Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.

About 13F filings

A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.

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