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.
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).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| FMR LLC added | 6,952,133 | $98M | 12.1% | 2026-Q1 |
| Fairmount Funds Management LLC | 4,553,494 | $64M | 7.9% | 2026-Q1 |
| RA CAPITAL MANAGEMENT, L.P. | 3,671,083 | $52M | 6.4% | 2026-Q1 |
| Bellevue Group AG added | 3,501,502 | $49M | 6.1% | 2026-Q1 |
| Venrock Adviser, LLC | 3,220,364 | $45M | 5.6% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC new | 3,105,669 | $44M | 5.4% | 2026-Q1 |
| Avidity Partners Management LP | 1,400,708 | $34M | 4.2% | 2026-Q1 |
| BlackRock, Inc. trimmed | 2,313,949 | $33M | 4.0% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,796,652 | $25M | 3.1% | 2026-Q1 |
| BAKER BROS. ADVISORS LP | 1,641,137 | $23M | 2.9% | 2026-Q1 |
| Remedium Capital Partners, LLC | 1,577,750 | $22M | 2.7% | 2026-Q1 |
| Versant Venture Management, LLC | 1,525,820 | $21M | 2.7% | 2026-Q1 |
| SAMSARA BIOCAPITAL, LLC | 968,798 | $14M | 1.7% | 2026-Q1 |
| GREAT POINT PARTNERS LLC added | 964,462 | $14M | 1.7% | 2026-Q1 |
| MARSHALL WACE, LLP added | 940,504 | $13M | 1.6% | 2026-Q1 |
| Aberdeen Group plc | 867,284 | $12M | 1.5% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC trimmed | 822,520 | $12M | 1.4% | 2026-Q1 |
| Soleus Capital Management, L.P. | 796,744 | $11M | 1.4% | 2026-Q1 |
| ACORN CAPITAL ADVISORS, LLC new | 786,760 | $11M | 1.4% | 2026-Q1 |
| STATE STREET CORP added | 655,690 | $9M | 1.1% | 2026-Q1 |
| Affinity Asset Advisors, LLC trimmed | 639,956 | $9M | 1.1% | 2026-Q1 |
| Driehaus Capital Management LLC trimmed | 635,498 | $9M | 1.1% | 2026-Q1 |
| RTW INVESTMENTS, LP trimmed | 573,205 | $8M | 1.0% | 2026-Q1 |
| Ikarian Capital, LLC added | 512,349 | $7M | 0.9% | 2026-Q1 |
| Opaleye Management Inc. | 427,608 | $6M | 0.7% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. added | 402,489 | $6M | 0.7% | 2026-Q1 |
| Logos Global Management LP added | 400,000 | $6M | 0.7% | 2026-Q1 |
| Foresite Capital Management VI LLC new | 320,000 | $4M | 0.6% | 2026-Q1 |
| Point72 Asset Management, L.P. trimmed | 264,315 | $4M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 241,905 | $3M | 0.4% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 219,497 | $3M | 0.4% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 211,319 | $3M | 0.4% | 2026-Q1 |
| ORBIMED ADVISORS LLC trimmed | 185,011 | $3M | 0.3% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. added | 169,051 | $2M | 0.3% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 160,051 | $2M | 0.3% | 2026-Q1 |
| STEMPOINT CAPITAL LP new | 154,034 | $2M | 0.3% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 153,037 | $2M | 0.3% | 2026-Q1 |
| BOOTHBAY FUND MANAGEMENT, LLC added | 139,968 | $2M | 0.2% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 137,222 | $2M | 0.2% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC added | 135,039 | $2M | 0.2% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP added | 129,166 | $2M | 0.2% | 2026-Q1 |
| Russell Investments Group, Ltd. added | 107,596 | $2M | 0.2% | 2026-Q1 |
| Sofinnova Investments, Inc. | 107,391 | $2M | 0.2% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 91,647 | $1M | 0.2% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 89,964 | $1M | 0.2% | 2026-Q1 |
| XTX Topco Ltd added | 78,108 | $1M | 0.1% | 2026-Q1 |
| UBS Group AG trimmed | 65,022 | $914K | 0.1% | 2026-Q1 |
| MORGAN STANLEY trimmed | 50,595 | $711K | 0.1% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. | 45,334 | $700K | 0.1% | 2026-Q1 |
| Nuveen, LLC trimmed | 46,236 | $650K | 0.1% | 2026-Q1 |
| Squarepoint Ops LLC added | 44,650 | $627K | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS trimmed | 40,551 | $570K | 0.1% | 2026-Q1 |
| DEUTSCHE BANK AG\ added | 39,199 | $551K | 0.1% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 38,598 | $542K | 0.1% | 2026-Q1 |
| SCHRODER INVESTMENT MANAGEMENT GROUP | 39,279 | $521K | 0.1% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC added | 33,369 | $469K | 0.1% | 2026-Q1 |
| Quantinno Capital Management LP added | 30,551 | $429K | 0.1% | 2026-Q1 |
| Invesco Ltd. trimmed | 29,560 | $415K | 0.1% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 28,624 | $402K | 0.0% | 2026-Q1 |
| Trexquant Investment LP new | 28,107 | $395K | 0.0% | 2026-Q1 |
| Y-Intercept (Hong Kong) Ltd new | 25,131 | $353K | 0.0% | 2026-Q1 |
| Qube Research & Technologies Ltd added | 24,792 | $348K | 0.0% | 2026-Q1 |
| BARCLAYS PLC trimmed | 24,660 | $346K | 0.0% | 2026-Q1 |
| HRT FINANCIAL LP added | 24,422 | $343K | 0.0% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 23,698 | $333K | 0.0% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ trimmed | 22,578 | $318K | 0.0% | 2026-Q1 |
| ADAR1 Capital Management, LLC trimmed | 20,000 | $281K | 0.0% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP trimmed | 19,555 | $275K | 0.0% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 18,308 | $257K | 0.0% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 18,251 | $256K | 0.0% | 2026-Q1 |
| Virtus Investment Advisers, LLC added | 18,203 | $256K | 0.0% | 2026-Q1 |
| MetLife Investment Management, LLC trimmed | 17,935 | $252K | 0.0% | 2026-Q1 |
| DELTEC ASSET MANAGEMENT LLC | 15,756 | $221K | 0.0% | 2026-Q1 |
| STATE OF WISCONSIN INVESTMENT BOARD trimmed | 15,021 | $211K | 0.0% | 2026-Q1 |
| JPMORGAN CHASE & CO trimmed | 15,863 | $210K | 0.0% | 2026-Q1 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. trimmed | 14,961 | $210K | 0.0% | 2026-Q1 |
| ExodusPoint Capital Management, LP trimmed | 14,131 | $199K | 0.0% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 12,046 | $169K | 0.0% | 2026-Q1 |
| VANGUARD GROUP INC added | 1,925,642 | $30M | 3.7% | 2025-Q4 stale |
| Deep Track Capital, LP trimmed | 2,279,892 | $20M | 2.4% | 2025-Q3 stale |
| Frazier Life Sciences Management, L.P. trimmed | 1,413,280 | $12M | 1.5% | 2025-Q3 stale |
| Caption Management, LLC added | 297,095 | $5M | 0.6% | 2025-Q4 stale |
| DEERFIELD MANAGEMENT COMPANY, L.P. | 531,163 | $5M | 0.6% | 2025-Q3 stale |
| Atlas Venture Life Science Advisors, LLC | 1,799,232 | $5M | 0.6% | 2025-Q1 stale |
| BRAIDWELL LP | 1,440,499 | $4M | 0.4% | 2025-Q1 stale |
| Allostery Investments LP added | 1,421,568 | $4M | 0.4% | 2025-Q1 stale |
| AMERIPRISE FINANCIAL INC new | 187,254 | $3M | 0.4% | 2025-Q4 stale |
| Blackstone Inc. added | 955,125 | $2M | 0.3% | 2025-Q1 stale |
| Jefferies Financial Group Inc. | 600,000 | $2M | 0.2% | 2025-Q1 stale |
| Cable Car Capital, LP new | 589,780 | $1M | 0.2% | 2025-Q1 stale |
| Woodline Partners LP trimmed | 82,056 | $1M | 0.2% | 2025-Q4 stale |
| 9823 Capital, L.P. new | 53,191 | $821K | 0.1% | 2025-Q4 stale |
| TWO SIGMA ADVISERS, LP added | 291,800 | $732K | 0.1% | 2025-Q1 stale |
| TCG Crossover Management, LLC trimmed | 64,023 | $640K | 0.1% | 2025-Q2 stale |
| TUDOR INVESTMENT CORP ET AL new | 24,200 | $373K | 0.0% | 2025-Q4 stale |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE added | 14,012 | $216K | 0.0% | 2025-Q4 stale |
| LOS ANGELES CAPITAL MANAGEMENT LLC new | 21,570 | $212K | 0.0% | 2025-Q4 stale |
| Persistent Asset Partners Ltd new | 12,469 | $192K | 0.0% | 2025-Q4 stale |
| INTECH INVESTMENT MANAGEMENT LLC trimmed | 11,802 | $182K | 0.0% | 2025-Q4 stale |
| TANG CAPITAL MANAGEMENT LLC new | 69,754 | $175K | 0.0% | 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.
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.