Who owns ARGX (ARGX)
Which tracked institutional funds hold ARGX, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See ARGX 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
83 tracked funds added or opened ARGX while 188 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
ARGX’s largest tracked holder by dollar value, FMR LLC, sizes it at 0.2% of its own reported 13F book, while the median holder sizes it at 0.1% 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 ARGX 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 475 tracked filers holding ARGX, 238 increased or opened the position and 272 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 ARGX 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 28
- ADAGE CAPITAL PARTNERS GP, L.L.C.$66M
- Jones Hill Capital LP$19M
- HSBC HOLDINGS PLC$15M
- MIROVA$14M
- CenterBook Partners LP$10M
- CVFG LLC$6M
Full exits 41
- TWO SIGMA ADVISERS, LP$114M
- ACADIAN ASSET MANAGEMENT LLC$99M
- SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC$69M
- ARMISTICE CAPITAL, LLC$49M
- Woodline Partners LP$38M
- Quadrature Capital Ltd$21M
Largest adds
- WELLINGTON MANAGEMENT GROUP LLP$175M
- Invesco Ltd.$81M
- BNP PARIBAS FINANCIAL MARKETS$70M
- BANK OF MONTREAL /CAN/$49M
- Capital World Investors$36M
- BRAIDWELL LP$36M
Largest trims
- FMR LLC$1.1B
- Artisan Partners Limited Partnership$406M
- BlackRock, Inc.$368M
- PRICE T ROWE ASSOCIATES INC /MD/$363M
- Clearbridge Investments, LLC$263M
- JANUS HENDERSON GROUP PLC$210M
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 trimmed | 4,991,034 | $3.6B | 17.5% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ added | 3,374,955 | $2.5B | 11.9% | 2026-Q1 |
| JANUS HENDERSON GROUP PLC added | 2,541,732 | $1.8B | 8.9% | 2026-Q1 |
| Capital World Investors added | 2,256,216 | $1.6B | 7.9% | 2026-Q1 |
| Artisan Partners Limited Partnership trimmed | 1,467,982 | $1.1B | 5.2% | 2026-Q1 |
| WELLINGTON MANAGEMENT GROUP LLP added | 1,021,457 | $746M | 3.6% | 2026-Q1 |
| Avoro Capital Advisors LLC added | 1,000,000 | $730M | 3.5% | 2026-Q1 |
| RTW INVESTMENTS, LP added | 709,446 | $518M | 2.5% | 2026-Q1 |
| Invesco Ltd. added | 590,188 | $431M | 2.1% | 2026-Q1 |
| MORGAN STANLEY added | 560,711 | $409M | 2.0% | 2026-Q1 |
| ALLIANCEBERNSTEIN L.P. added | 422,304 | $355M | 1.7% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ trimmed | 400,117 | $292M | 1.4% | 2026-Q1 |
| BlackRock, Inc. trimmed | 343,211 | $251M | 1.2% | 2026-Q1 |
| SANDS CAPITAL MANAGEMENT, LLC trimmed | 340,285 | $248M | 1.2% | 2026-Q1 |
| Bellevue Group AG trimmed | 313,000 | $229M | 1.1% | 2026-Q1 |
| SEI INVESTMENTS CO trimmed | 286,966 | $210M | 1.0% | 2026-Q1 |
| WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC added | 266,067 | $194M | 0.9% | 2026-Q1 |
| JENNISON ASSOCIATES LLC added | 237,468 | $173M | 0.8% | 2026-Q1 |
| FRANKLIN RESOURCES INC trimmed | 233,493 | $171M | 0.8% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 231,985 | $169M | 0.8% | 2026-Q1 |
| Clearbridge Investments, LLC trimmed | 231,356 | $169M | 0.8% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 219,126 | $160M | 0.8% | 2026-Q1 |
| Fiera Capital Corp trimmed | 217,198 | $159M | 0.8% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC added | 215,910 | $158M | 0.8% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC added | 175,311 | $130M | 0.6% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 177,836 | $130M | 0.6% | 2026-Q1 |
| AMERICAN CENTURY COMPANIES INC trimmed | 173,700 | $127M | 0.6% | 2026-Q1 |
| Checkpoint Capital L.P. added | 153,000 | $112M | 0.5% | 2026-Q1 |
| LORD, ABBETT & CO. LLC trimmed | 152,083 | $111M | 0.5% | 2026-Q1 |
| Legal & General Group Plc added | 150,850 | $110M | 0.5% | 2026-Q1 |
| Pictet Asset Management Holding SA trimmed | 148,306 | $108M | 0.5% | 2026-Q1 |
| DEUTSCHE BANK AG\ added | 139,381 | $102M | 0.5% | 2026-Q1 |
| BAMCO INC /NY/ trimmed | 138,648 | $101M | 0.5% | 2026-Q1 |
| ORBIMED ADVISORS LLC trimmed | 136,900 | $100M | 0.5% | 2026-Q1 |
| LAZARD ASSET MANAGEMENT LLC added | 133,347 | $97M | 0.5% | 2026-Q1 |
| BNP PARIBAS ASSET MANAGEMENT Holding S.A. added | 129,147 | $94M | 0.5% | 2026-Q1 |
| EVENTIDE ASSET MANAGEMENT, LLC added | 125,657 | $92M | 0.4% | 2026-Q1 |
| AGF MANAGEMENT LTD added | 125,069 | $91M | 0.4% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP trimmed | 109,121 | $80M | 0.4% | 2026-Q1 |
| FIRST TRUST ADVISORS LP added | 107,195 | $78M | 0.4% | 2026-Q1 |
| PINEBRIDGE INVESTMENTS LLC added | 103,812 | $76M | 0.4% | 2026-Q1 |
| Rock Springs Capital Management LP trimmed | 98,500 | $72M | 0.3% | 2026-Q1 |
| FEDERATED HERMES, INC. trimmed | 95,253 | $70M | 0.3% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. trimmed | 90,000 | $66M | 0.3% | 2026-Q1 |
| BANK OF MONTREAL /CAN/ added | 85,333 | $62M | 0.3% | 2026-Q1 |
| BRAIDWELL LP added | 84,939 | $62M | 0.3% | 2026-Q1 |
| 1832 Asset Management L.P. trimmed | 84,200 | $61M | 0.3% | 2026-Q1 |
| TimesSquare Capital Management, LLC trimmed | 83,117 | $61M | 0.3% | 2026-Q1 |
| Aberdeen Group plc added | 82,106 | $60M | 0.3% | 2026-Q1 |
| TD Asset Management Inc trimmed | 80,824 | $59M | 0.3% | 2026-Q1 |
| Eagle Health Investments LP added | 76,336 | $56M | 0.3% | 2026-Q1 |
| Public Sector Pension Investment Board added | 73,300 | $54M | 0.3% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 72,365 | $53M | 0.3% | 2026-Q1 |
| Ensign Peak Advisors, Inc trimmed | 71,598 | $52M | 0.3% | 2026-Q1 |
| PGGM Investments added | 71,514 | $52M | 0.3% | 2026-Q1 |
| Nuveen, LLC | 66,241 | $48M | 0.2% | 2026-Q1 |
| BESSEMER GROUP INC added | 64,251 | $47M | 0.2% | 2026-Q1 |
| Amundi added | 61,433 | $45M | 0.2% | 2026-Q1 |
| ENVESTNET ASSET MANAGEMENT INC trimmed | 61,418 | $45M | 0.2% | 2026-Q1 |
| Life Cycle Investment Partners Ltd added | 58,867 | $43M | 0.2% | 2026-Q1 |
| NORTHERN TRUST CORP trimmed | 58,706 | $43M | 0.2% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. added | 58,374 | $43M | 0.2% | 2026-Q1 |
| Handelsbanken Fonder AB added | 54,926 | $40M | 0.2% | 2026-Q1 |
| Candriam S.C.A. added | 54,148 | $40M | 0.2% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 52,122 | $38M | 0.2% | 2026-Q1 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE trimmed | 49,330 | $36M | 0.2% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT CO LTD trimmed | 49,306 | $36M | 0.2% | 2026-Q1 |
| VAN ECK ASSOCIATES CORP added | 40,397 | $30M | 0.1% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND trimmed | 39,437 | $29M | 0.1% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 38,794 | $28M | 0.1% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 38,438 | $28M | 0.1% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 38,104 | $28M | 0.1% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC trimmed | 36,802 | $27M | 0.1% | 2026-Q1 |
| Patient Square Capital LP added | 36,718 | $27M | 0.1% | 2026-Q1 |
| Davern Capital Partners, LP trimmed | 35,045 | $26M | 0.1% | 2026-Q1 |
| ROYAL BANK OF CANADA trimmed | 32,917 | $24M | 0.1% | 2026-Q1 |
| VICTORY CAPITAL MANAGEMENT INC trimmed | 32,255 | $24M | 0.1% | 2026-Q1 |
| UBS Group AG trimmed | 31,647 | $23M | 0.1% | 2026-Q1 |
| Tri Locum Partners LP trimmed | 31,635 | $23M | 0.1% | 2026-Q1 |
| Jefferies Financial Group Inc. added | 30,005 | $22M | 0.1% | 2026-Q1 |
| Hudson Bay Capital Management LP added | 30,000 | $22M | 0.1% | 2026-Q1 |
| Artia Global Partners LP trimmed | 29,739 | $22M | 0.1% | 2026-Q1 |
| Perpetual Ltd trimmed | 28,359 | $21M | 0.1% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 27,506 | $20M | 0.1% | 2026-Q1 |
| ALKEON CAPITAL MANAGEMENT LLC added | 175,000 | $129M | 0.6% | 2025-Q3 stale |
| TWO SIGMA ADVISERS, LP trimmed | 135,500 | $114M | 0.5% | 2025-Q4 stale |
| ACADIAN ASSET MANAGEMENT LLC added | 117,887 | $99M | 0.5% | 2025-Q4 stale |
| PINEBRIDGE INVESTMENTS, L.P. added | 95,723 | $71M | 0.3% | 2025-Q3 stale |
| SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC trimmed | 82,620 | $69M | 0.3% | 2025-Q4 stale |
| Caisse de depot et placement du Quebec trimmed | 73,595 | $54M | 0.3% | 2025-Q3 stale |
| ARMISTICE CAPITAL, LLC | 58,000 | $49M | 0.2% | 2025-Q4 stale |
| Woodline Partners LP trimmed | 45,426 | $38M | 0.2% | 2025-Q4 stale |
| Paradigm Biocapital Advisors LP trimmed | 59,679 | $35M | 0.2% | 2025-Q1 stale |
| PERCEPTIVE ADVISORS LLC trimmed | 59,510 | $35M | 0.2% | 2025-Q1 stale |
| Railway Pension Investments Ltd | 39,500 | $22M | 0.1% | 2025-Q2 stale |
| Quadrature Capital Ltd trimmed | 25,399 | $21M | 0.1% | 2025-Q4 stale |
| MOORE CAPITAL MANAGEMENT, LP added | 25,000 | $21M | 0.1% | 2025-Q4 stale |
| ARDSLEY ADVISORY PARTNERS LP added | 24,000 | $20M | 0.1% | 2025-Q4 stale |
| AXA Investment Managers S.A. new | 26,710 | $20M | 0.1% | 2025-Q3 stale |
| First Turn Management, LLC trimmed | 23,256 | $20M | 0.1% | 2025-Q4 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.