Who owns JANX (JANX)
Which tracked institutional funds hold JANX, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See JANX 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
47 tracked funds added or opened JANX while 45 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
JANX’s largest tracked holder by dollar value, RA CAPITAL MANAGEMENT, L.P., sizes it at 1.6% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 1.6pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in JANX 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 189 tracked filers holding JANX, 112 increased or opened the position and 86 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
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 JANX 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 15
- VANGUARD CAPITAL MANAGEMENT LLC$25M
- VANGUARD PORTFOLIO MANAGEMENT LLC$18M
- Nantahala Capital Management, LLC$11M
- Irenic Capital Management LP$11M
- TANG CAPITAL MANAGEMENT LLC$7M
- VANGUARD FIDUCIARY TRUST CO$4M
Full exits 14
- VANGUARD GROUP INC$35M
- Cormorant Asset Management, LP$9M
- ADAGE CAPITAL PARTNERS GP, L.L.C.$6M
- University of Wisconsin Foundation$5M
- Pictet Asset Management Holding SA$4M
- Rhenman & Partners Asset Management AB$3M
Largest adds
- BlackRock, Inc.$19M
- Prosight Management, LP$16M
- Deep Track Capital, LP$15M
- HRT FINANCIAL LP$5M
- Alyeska Investment Group, L.P.$4M
- Man Group plc$4M
Largest trims
- STATE STREET CORP$19M
- FMR LLC$17M
- JANUS HENDERSON GROUP PLC$16M
- ORBIMED ADVISORS LLC$13M
- READYSTATE ASSET MANAGEMENT LP$11M
- CITADEL ADVISORS LLC$10M
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 |
|---|---|---|---|---|
| RA CAPITAL MANAGEMENT, L.P. | 11,189,693 | $156M | 14.4% | 2026-Q1 |
| BlackRock, Inc. added | 5,433,233 | $76M | 7.0% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC trimmed | 4,196,409 | $58M | 5.4% | 2026-Q1 |
| Prosight Management, LP added | 3,550,000 | $49M | 4.6% | 2026-Q1 |
| STATE STREET CORP trimmed | 2,464,017 | $34M | 3.2% | 2026-Q1 |
| FMR LLC trimmed | 2,259,354 | $31M | 2.9% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 1,811,365 | $25M | 2.3% | 2026-Q1 |
| TCG Crossover Management, LLC | 1,789,617 | $25M | 2.3% | 2026-Q1 |
| Alyeska Investment Group, L.P. added | 1,601,089 | $22M | 2.1% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 1,495,948 | $21M | 1.9% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 1,290,256 | $18M | 1.7% | 2026-Q1 |
| Deep Track Capital, LP added | 1,187,290 | $17M | 1.5% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 1,156,140 | $16M | 1.5% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,146,724 | $16M | 1.5% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. added | 1,090,147 | $15M | 1.4% | 2026-Q1 |
| Logos Global Management LP | 1,000,000 | $14M | 1.3% | 2026-Q1 |
| ORBIMED ADVISORS LLC trimmed | 983,600 | $14M | 1.3% | 2026-Q1 |
| Nantahala Capital Management, LLC new | 809,914 | $11M | 1.0% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 801,646 | $11M | 1.0% | 2026-Q1 |
| Irenic Capital Management LP new | 765,804 | $11M | 1.0% | 2026-Q1 |
| Woodline Partners LP trimmed | 738,032 | $10M | 0.9% | 2026-Q1 |
| MORGAN STANLEY added | 703,940 | $10M | 0.9% | 2026-Q1 |
| Squarepoint Ops LLC added | 604,000 | $8M | 0.8% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 602,013 | $8M | 0.8% | 2026-Q1 |
| TANG CAPITAL MANAGEMENT LLC trimmed | 500,000 | $7M | 0.6% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 443,397 | $6M | 0.6% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 386,810 | $5M | 0.5% | 2026-Q1 |
| Nationale-Nederlanden Powszechne Towarzystwo Emerytalne S.A. | 376,496 | $5M | 0.5% | 2026-Q1 |
| Rock Springs Capital Management LP added | 367,009 | $5M | 0.5% | 2026-Q1 |
| HRT FINANCIAL LP added | 366,699 | $5M | 0.5% | 2026-Q1 |
| NORTHERN TRUST CORP added | 362,180 | $5M | 0.5% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 354,328 | $5M | 0.5% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 352,177 | $5M | 0.5% | 2026-Q1 |
| Man Group plc added | 342,986 | $5M | 0.4% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 313,648 | $4M | 0.4% | 2026-Q1 |
| ADAR1 Capital Management, LLC added | 298,546 | $4M | 0.4% | 2026-Q1 |
| JANE STREET GROUP, LLC trimmed | 251,740 | $3M | 0.3% | 2026-Q1 |
| Jump Financial, LLC added | 221,800 | $3M | 0.3% | 2026-Q1 |
| UBS Group AG trimmed | 219,806 | $3M | 0.3% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 229,268 | $3M | 0.3% | 2026-Q1 |
| Qube Research & Technologies Ltd trimmed | 197,145 | $3M | 0.3% | 2026-Q1 |
| SCHRODER INVESTMENT MANAGEMENT GROUP trimmed | 195,160 | $3M | 0.2% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC added | 168,976 | $2M | 0.2% | 2026-Q1 |
| BML Capital Management, LLC new | 154,961 | $2M | 0.2% | 2026-Q1 |
| Y-Intercept (Hong Kong) Ltd added | 139,967 | $2M | 0.2% | 2026-Q1 |
| Walleye Capital LLC trimmed | 130,618 | $2M | 0.2% | 2026-Q1 |
| Rangeley Capital, LLC added | 122,500 | $2M | 0.2% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 119,826 | $2M | 0.2% | 2026-Q1 |
| Connor, Clark & Lunn Investment Management Ltd. added | 119,376 | $2M | 0.2% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 119,055 | $2M | 0.2% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP trimmed | 116,099 | $2M | 0.1% | 2026-Q1 |
| CAPITAL FUND MANAGEMENT S.A. added | 115,867 | $2M | 0.1% | 2026-Q1 |
| ExodusPoint Capital Management, LP trimmed | 114,572 | $2M | 0.1% | 2026-Q1 |
| Hudson Bay Capital Management LP | 110,000 | $2M | 0.1% | 2026-Q1 |
| READYSTATE ASSET MANAGEMENT LP trimmed | 109,425 | $2M | 0.1% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 105,300 | $1M | 0.1% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 98,395 | $1M | 0.1% | 2026-Q1 |
| Nuveen, LLC added | 97,120 | $1M | 0.1% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP trimmed | 96,630 | $1M | 0.1% | 2026-Q1 |
| Aquatic Capital Management LLC added | 93,974 | $1M | 0.1% | 2026-Q1 |
| Weiss Asset Management LP new | 93,144 | $1M | 0.1% | 2026-Q1 |
| FRANKLIN RESOURCES INC trimmed | 90,101 | $1M | 0.1% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 87,757 | $1M | 0.1% | 2026-Q1 |
| Swiss National Bank | 77,100 | $1M | 0.1% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. | 76,601 | $1M | 0.1% | 2026-Q1 |
| Rafferty Asset Management, LLC trimmed | 75,732 | $1M | 0.1% | 2026-Q1 |
| Paradigm Biocapital Advisors LP | 2,920,258 | $71M | 6.6% | 2025-Q3 stale |
| VANGUARD GROUP INC added | 2,549,288 | $35M | 3.3% | 2025-Q4 stale |
| EcoR1 Capital, LLC | 1,469,818 | $34M | 3.1% | 2025-Q2 stale |
| LORD, ABBETT & CO. LLC trimmed | 667,881 | $18M | 1.7% | 2025-Q1 stale |
| First Turn Management, LLC added | 639,699 | $16M | 1.4% | 2025-Q3 stale |
| MPM BIOIMPACT LLC | 614,282 | $15M | 1.4% | 2025-Q3 stale |
| Cormorant Asset Management, LP trimmed | 650,000 | $9M | 0.8% | 2025-Q4 stale |
| Aberdeen Group plc added | 345,476 | $8M | 0.8% | 2025-Q3 stale |
| PERCEPTIVE ADVISORS LLC | 292,686 | $7M | 0.7% | 2025-Q3 stale |
| Avidity Partners Management LP trimmed | 258,000 | $7M | 0.6% | 2025-Q1 stale |
| Cubist Systematic Strategies, LLC added | 257,527 | $6M | 0.6% | 2025-Q3 stale |
| AMERIPRISE FINANCIAL INC added | 256,055 | $6M | 0.6% | 2025-Q3 stale |
| ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed | 400,000 | $6M | 0.5% | 2025-Q4 stale |
| University of Wisconsin Foundation new | 362,000 | $5M | 0.5% | 2025-Q4 stale |
| Skandinaviska Enskilda Banken AB (publ) | 177,820 | $4M | 0.4% | 2025-Q2 stale |
| Pictet Asset Management Holding SA trimmed | 272,251 | $4M | 0.3% | 2025-Q4 stale |
| First Light Asset Management, LLC trimmed | 149,596 | $3M | 0.3% | 2025-Q2 stale |
| Rhenman & Partners Asset Management AB added | 225,377 | $3M | 0.3% | 2025-Q4 stale |
| FIRST TRUST ADVISORS LP trimmed | 114,502 | $3M | 0.3% | 2025-Q1 stale |
| LAZARD ASSET MANAGEMENT LLC trimmed | 97,473 | $2M | 0.2% | 2025-Q3 stale |
| Trexquant Investment LP added | 170,484 | $2M | 0.2% | 2025-Q4 stale |
| Ally Bridge Group (NY) LLC trimmed | 81,292 | $2M | 0.2% | 2025-Q1 stale |
| SPHERA FUNDS MANAGEMENT LTD. added | 157,840 | $2M | 0.2% | 2025-Q4 stale |
| Springhill Fund Asset Management (HK) Co Ltd added | 78,500 | $2M | 0.2% | 2025-Q1 stale |
| STEMPOINT CAPITAL LP trimmed | 89,933 | $2M | 0.2% | 2025-Q2 stale |
| MACQUARIE GROUP LTD | 76,601 | $2M | 0.2% | 2025-Q3 stale |
| E Fund Management Co., Ltd. added | 68,644 | $2M | 0.2% | 2025-Q1 stale |
| Quinn Opportunity Partners LLC | 59,893 | $1M | 0.1% | 2025-Q3 stale |
| TWO SIGMA ADVISERS, LP added | 104,100 | $1M | 0.1% | 2025-Q4 stale |
| Blue Owl Capital Holdings LP added | 100,000 | $1M | 0.1% | 2025-Q4 stale |
| Ikarian Capital, LLC trimmed | 54,691 | $1M | 0.1% | 2025-Q3 stale |
| AVALON VENTURES MANAGEMENT, LLC added | 53,300 | $1M | 0.1% | 2025-Q3 stale |
| Ratan Capital Management LP trimmed | 13,288 | $1M | 0.1% | 2025-Q2 stale |
| Magnetar Financial LLC added | 41,055 | $1M | 0.1% | 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.