% of shares outstanding not shown: this line files 20-F annual reports only — a foreign private issuer whose US listing trades as ADSs (depositary receipts), while its cover-page share count is in ORDINARY shares. The depositary ratio is not in our data. The count we hold for this line is 61,883,306 shares (as of 2025-12-31, source dei). Dividing one by the other is wrong by the whole ratio (a 5:1 ADR reads one fifth of the true percentage), so the percentage is withheld rather than served wrong. Holder share counts are shown as filed.
Crowding percentile withheld — no market cap for ARGX in the served universe — the cohort is size-matched, and an unmatched percentile would compare a micro-cap register to a mega-cap one.
| # | Holder | Shares | Value | % of shares out | Δ QoQ |
|---|---|---|---|---|---|
| 1 | FMR LLC | 4,991,0345.0M | $3.6B | — | TRIM -11% |
| 2 | PRICE T ROWE ASSOCIATES INC /MD/ | 3,374,9553.4M | $2.5B | — | — |
| 3 | JANUS HENDERSON GROUP PLC | 2,541,7322.5M | $1.8B | — | ADD 3% |
| 4 | Capital World Investors | 2,256,2162.3M | $1.6B | — | ADD 18% |
| 5 | Artisan Partners Limited Partnership | 1,467,9821.5M | $1.1B | — | TRIM -16% |
| 6 | WELLINGTON MANAGEMENT GROUP LLP | 1,021,4571.0M | $746M | — | ADD 50% |
| 7 | Avoro Capital Advisors LLC | 1,000,0001.0M | $730M | — | — |
| 8 | BlackRock, Inc. | 808,337808,337 | $590M | — | ADD 10% |
| 9 | RTW INVESTMENTS, LP | 709,446709,446 | $518M | — | ADD 5% |
| 10 | Invesco Ltd. | 594,697594,697 | $434M | — | ADD 43% |
| 11 | MORGAN STANLEY | 560,711560,711 | $409M | — | ADD 8% |
| 12 | ALLIANCEBERNSTEIN L.P. | 422,304422,304 | $355M | — | — |
| 13 | BANK OF AMERICA CORP /DE/ | 400,117400,117 | $292M | — | — |
| 14 | SANDS CAPITAL MANAGEMENT, LLC | 340,285340,285 | $248M | — | TRIM -5% |
| 15 | Bellevue Group AG | 313,000313,000 | $229M | — | TRIM -32% |
| 16 | SEI INVESTMENTS CO | 286,966286,966 | $210M | — | TRIM -13% |
| 17 | WILLIAM BLAIR INVESTMENT MANAGEMENT, LLC | 266,067266,067 | $194M | — | ADD 19% |
| 18 | JENNISON ASSOCIATES LLC | 237,468237,468 | $173M | — | ADD 3% |
| 19 | FRANKLIN RESOURCES INC | 233,493233,493 | $171M | — | — |
| 20 | GOLDMAN SACHS GROUP INC | 231,985231,985 | $169M | — | ADD 39% |
| 21 | Clearbridge Investments, LLC | 231,356231,356 | $169M | — | TRIM -55% |
| 22 | CITADEL ADVISORS LLC | 219,126219,126 | $160M | — | TRIM -38% |
| 23 | Fiera Capital Corp | 217,198217,198 | $159M | — | TRIM -4% |
| 24 | AMERIPRISE FINANCIAL INC | 215,910215,910 | $158M | — | ADD 15% |
| 25 | Allspring Global Investments Holdings, LLC | 175,311175,311 | $130M | — | — |
| 26 | BNP PARIBAS FINANCIAL MARKETS | 177,836177,836 | $130M | — | ADD 151% |
| 27 | AMERICAN CENTURY COMPANIES INC | 173,700173,700 | $127M | — | TRIM -21% |
| 28 | Checkpoint Capital L.P. | 153,000153,000 | $112M | — | ADD 8% |
| 29 | LORD, ABBETT & CO. LLC | 152,083152,083 | $111M | — | TRIM -25% |
| 30 | Legal & General Group Plc | 150,850150,850 | $110M | — | ADD 4% |
| 31 | Pictet Asset Management Holding SA | 148,306148,306 | $108M | — | TRIM -3% |
| 32 | DEUTSCHE BANK AG\ | 139,381139,381 | $102M | — | ADD 3% |
| 33 | BAMCO INC /NY/ | 138,648138,648 | $101M | — | TRIM -10% |
| 34 | ORBIMED ADVISORS LLC | 136,900136,900 | $100M | — | TRIM -6% |
| 35 | LAZARD ASSET MANAGEMENT LLC | 133,347133,347 | $97M | — | — |
| 36 | BNP PARIBAS ASSET MANAGEMENT Holding S.A. | 129,147129,147 | $94M | — | ADD 12% |
| 37 | EVENTIDE ASSET MANAGEMENT, LLC | 125,657125,657 | $92M | — | ADD 4% |
| 38 | AGF MANAGEMENT LTD | 125,069125,069 | $91M | — | — |
| 39 | TWO SIGMA INVESTMENTS, LP | 109,121109,121 | $80M | — | TRIM -58% |
| 40 | FIRST TRUST ADVISORS LP | 107,195107,195 | $78M | — | ADD 99% |
| 41 | PINEBRIDGE INVESTMENTS LLC | 103,812103,812 | $76M | — | ADD 44% |
| 42 | Rock Springs Capital Management LP | 98,50098,500 | $72M | — | TRIM -5% |
| 43 | FEDERATED HERMES, INC. | 95,25395,253 | $70M | — | TRIM -11% |
| 44 | ADAGE CAPITAL PARTNERS GP, L.L.C. | 90,00090,000 | $66M | — | NEW |
| 45 | BANK OF MONTREAL /CAN/ | 85,33385,333 | $62M | — | ADD 421% |
| 46 | BRAIDWELL LP | 84,93984,939 | $62M | — | ADD 174% |
| 47 | 1832 Asset Management L.P. | 84,20084,200 | $61M | — | TRIM -24% |
| 48 | TimesSquare Capital Management, LLC | 83,11783,117 | $61M | — | TRIM -23% |
| 49 | Aberdeen Group plc | 82,10682,106 | $60M | — | ADD 57% |
| 50 | TD Asset Management Inc | 80,82480,824 | $59M | — | TRIM -20% |
| 51 | Eagle Health Investments LP | 76,33676,336 | $56M | — | ADD 22% |
| 52 | Public Sector Pension Investment Board | 73,30073,300 | $54M | — | ADD 100% |
| 53 | MILLENNIUM MANAGEMENT LLC | 72,36572,365 | $53M | — | ADD 20% |
| 54 | Ensign Peak Advisors, Inc | 71,59871,598 | $52M | — | TRIM -21% |
| 55 | PGGM Investments | 71,51471,514 | $52M | — | ADD 30% |
| 56 | Nuveen, LLC | 66,24166,241 | $48M | — | — |
| 57 | BESSEMER GROUP INC | 64,25164,251 | $47M | — | ADD 3% |
| 58 | Amundi | 61,43361,433 | $45M | — | ADD 45% |
| 59 | ENVESTNET ASSET MANAGEMENT INC | 61,41861,418 | $45M | — | TRIM -23% |
| 60 | Life Cycle Investment Partners Ltd | 58,86758,867 | $43M | — | ADD 28% |
| 61 | NORTHERN TRUST CORP | 58,70658,706 | $43M | — | TRIM -9% |
| 62 | NOMURA ASSET MANAGEMENT INTERNATIONAL INC. | 58,37458,374 | $43M | — | ADD 29% |
| 63 | Handelsbanken Fonder AB | 54,92654,926 | $40M | — | ADD 4% |
| 64 | Candriam S.C.A. | 54,14854,148 | $40M | — | ADD 11% |
| 65 | D. E. Shaw & Co., Inc. | 52,12252,122 | $38M | — | ADD 14% |
| 66 | MANUFACTURERS LIFE INSURANCE COMPANY, THE | 49,33049,330 | $36M | — | TRIM -14% |
| 67 | NOMURA ASSET MANAGEMENT CO LTD | 49,30649,306 | $36M | — | — |
| 68 | VAN ECK ASSOCIATES CORP | 40,39740,397 | $30M | — | ADD 17% |
| 69 | NEW YORK STATE COMMON RETIREMENT FUND | 39,43739,437 | $29M | — | TRIM -10% |
| 70 | DIMENSIONAL FUND ADVISORS LP | 38,79438,794 | $28M | — | ADD 5% |
| 71 | JANE STREET GROUP, LLC | 38,43838,438 | $28M | — | ADD 35% |
| 72 | WELLS FARGO & COMPANY/MN | 38,10438,104 | $28M | — | TRIM -30% |
| 73 | RAYMOND JAMES FINANCIAL INC | 36,80236,802 | $27M | — | TRIM -36% |
| 74 | Patient Square Capital LP | 36,71836,718 | $27M | — | ADD 41% |
| 75 | Davern Capital Partners, LP | 35,04535,045 | $26M | — | — |
| 76 | ROYAL BANK OF CANADA | 32,91732,917 | $24M | — | TRIM -8% |
| 77 | VICTORY CAPITAL MANAGEMENT INC | 32,25532,255 | $24M | — | TRIM -5% |
| 78 | UBS Group AG | 31,64731,647 | $23M | — | TRIM -48% |
| 79 | Tri Locum Partners LP | 31,63531,635 | $23M | — | TRIM -16% |
| 80 | Jefferies Financial Group Inc. | 30,00530,005 | $22M | — | — |
| 81 | Hudson Bay Capital Management LP | 30,00030,000 | $22M | — | ADD 37% |
| 82 | Artia Global Partners LP | 29,73929,739 | $22M | — | TRIM -54% |
| 83 | Perpetual Ltd | 28,35928,359 | $21M | — | TRIM -8% |
| 84 | UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC | 27,50627,506 | $20M | — | ADD 28% |
| 85 | Jones Hill Capital LP | 25,99525,995 | $19M | — | NEW |
| 86 | Qube Research & Technologies Ltd | 25,53625,536 | $19M | — | ADD 14% |
| 87 | BAKER BROS. ADVISORS LP | 25,17425,174 | $18M | — | — |
| 88 | ODDO BHF ASSET MANAGEMENT SAS | 25,00925,009 | $18M | — | ADD 7% |
| 89 | GEODE CAPITAL MANAGEMENT, LLC | 23,56923,569 | $17M | — | — |
| 90 | LMR Partners LLP | 23,48823,488 | $17M | — | ADD 517% |
| 91 | LPL Financial LLC | 23,24723,247 | $17M | — | TRIM -9% |
| 92 | VOLORIDGE INVESTMENT MANAGEMENT, LLC | 22,65122,651 | $17M | — | ADD 61% |
| 93 | BLAIR WILLIAM & CO/IL | 22,40722,407 | $16M | — | TRIM -15% |
| 94 | NATIXIS ADVISORS, LLC | 20,38020,380 | $15M | — | TRIM -9% |
| 95 | HSBC HOLDINGS PLC | 20,37920,379 | $15M | — | NEW |
| 96 | SCHRODER INVESTMENT MANAGEMENT GROUP | 21,02321,023 | $15M | — | ADD 82% |
| 97 | MIROVA | 19,83319,833 | $14M | — | NEW |
| 98 | HRT FINANCIAL LP | 18,75418,754 | $14M | — | TRIM -5% |
| 99 | Squarepoint Ops LLC | 18,67918,679 | $14M | — | TRIM -34% |
| 100 | Bank of New York Mellon Corp | 17,18317,183 | $13M | — | ADD 4% |
Rows rank by the value each filer reported — 13F filers price their own positions, so a holder with fewer shares can rank just above one with more.
| Holder | 2024-Q4 | 2025-Q1 | 2025-Q2 | 2025-Q3 | 2025-Q4 | 2026-Q1 | Latest value |
|---|---|---|---|---|---|---|---|
| FMR LLC | 5.6M | 5.7M | 5.4M | 5.7M | 5.6M | 5.0M | $3.6B |
| PRICE T ROWE ASSOCIATES INC /MD/ | 5.5M | 5.4M | 5.0M | 3.6M | 3.4M | 3.4M | $2.5B |
| JANUS HENDERSON GROUP PLC | 2.3M | 2.1M | 2.6M | 2.6M | 2.5M | 2.5M | $1.8B |
| Capital World Investors | 1.8M | 1.9M | 2.0M | 2.0M | 1.9M | 2.3M | $1.6B |
| Artisan Partners Limited Partnership | 3.1M | 2.8M | 2.3M | 2.2M | 1.8M | 1.5M | $1.1B |
| WELLINGTON MANAGEMENT GROUP LLP | 425K | 406K | 405K | 730K | 679K | 1.0M | $746M |
| Avoro Capital Advisors LLC | 1.2M | 1.2M | 1.2M | 990K | 990K | 1.0M | $730M |
| BlackRock, Inc. | 1.1M | 1.0M | 550K | 524K | 736K | 808K | $590M |
| RTW INVESTMENTS, LP | 673K | 673K | 673K | 673K | 673K | 709K | $518M |
| Invesco Ltd. | 404K | 383K | 244K | 85K | 416K | 595K | $434M |
| MORGAN STANLEY | 939K | 877K | 429K | 435K | 519K | 561K | $409M |
| ALLIANCEBERNSTEIN L.P. | 20K | 1K | 54K | 85K | 414K | 422K | $355M |
| BANK OF AMERICA CORP /DE/ | 259K | 340K | 336K | 342K | 401K | 400K | $292M |
| SANDS CAPITAL MANAGEMENT, LLC | — | — | — | 17K | 357K | 340K | $248M |
| Bellevue Group AG | 593K | 579K | 571K | 546K | 462K | 313K | $229M |
Shares reported each quarter by the largest current holders. Green = added vs the prior filing, red = trimmed, grey = roughly held; a dash is a quarter with no 13F on file (a gap is skipped, not read as an exit). 13F is filed up to 45 days after quarter-end. Up to 40 quarters (10 years) available — use the selector above.
Holder count only — too few computable %-of-shares-outstanding quarters for a % pane. Line breaks are quarters with no 13F record, never interpolated.
Short interest has its own tab now — open SI →
Source: SEC Form 13F — every institution manager (≥ $100M in 13F securities) reporting a long US-listed position, across ~10,250 filers over 10 years of history. 13F is long-only, US-listed, filed up to 45 days after quarter-end.
Source: SEC Schedule 13D/13G structured XML. 13D = active intent; 13G filers report passively (Rule 13d-1(b) QII / 13d-1(c) Passive / 13d-1(d) Exempt) and are not activists. Percent and delta are the group aggregate the filing reports. Structured 13D/G coverage begins December 2024 (SEC XML mandate).
| Biggest buyers | Δ shares | Δ value | |
|---|---|---|---|
| WELLINGTON MANAGEMENT GROUP LLP | +342,221 | $250M | ADD |
| Capital World Investors | +339,982 | $248M | ADD |
| Invesco Ltd. | +178,289 | $130M | ADD |
| BNP PARIBAS FINANCIAL MARKETS | +107,092 | $78M | ADD |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | +90,000 | $66M | OPEN |
| Biggest sellers | Δ shares | Δ value | |
|---|---|---|---|
| FMR LLC | −601,285 | $439M | TRIM |
| Artisan Partners Limited Partnership | −288,960 | $211M | TRIM |
| Clearbridge Investments, LLC | −282,408 | $206M | TRIM |
| Corient Private Wealth LLC | −246,462 | $180M | TRIM |
| VOYA INVESTMENT MANAGEMENT LLC | −163,553 | $119M | TRIM |
The 2025-Q4 register is as-filed in ITS OWN share basis; every count below was rebased into the 2026-Q1 basis (no split in between, factor 1). Dollar figures value the SHARE delta at one price — the 2026-03-31 close — rather than differencing two filings' own reported values, which would mix the quarter's price move into the trade figure.
13Fs disclose LONG US-listed positions only — shorts, most derivatives, bonds and non-US listings are invisible here, and a filer's quarter-over-quarter change is not necessarily a trade (index rebalances, in-kind transfers and entity successions all read as flow).
| Quarter | Holders | Shares held | % shares out | Value held |
|---|---|---|---|---|
| 2026-Q1 | 474 | 28,815,132 | — | $21.1B |
| 2025-Q4 | 507 | 29,994,894 | — | $25.0B |
| 2025-Q3 | 468 | 30,532,864 | — | $22.5B |
| 2025-Q2 | 437 | 32,158,240 | — | $17.7B |
| 2025-Q1 | 447 | 33,382,893 | — | $19.7B |
| 2024-Q4 | 396 | 34,137,571 | — | $21.0B |
| 2024-Q3 | 357 | 35,062,078 | — | $19.0B |
| 2024-Q2 | 335 | 34,451,514 | — | $14.8B |
| 2024-Q1 | 327 | 35,380,828 | — | $13.9B |
| 2023-Q4 | 345 | 33,453,077 | — | $12.7B |
| 2023-Q3 | 340 | 32,689,816 | — | $16.1B |
| 2023-Q2 | 289 | 31,030,194 | — | $12.1B |
| 2023-Q1 | 271 | 36,569,782 | — | $13.6B |
| 2022-Q4 | 270 | 30,762,918 | — | $11.6B |
| 2022-Q3 | 254 | 32,353,121 | — | $11.4B |
| 2022-Q2 | 231 | 32,932,834 | — | $12.5B |
| 2022-Q1 | 198 | 32,304,279 | — | $10.2B |
| 2021-Q4 | 207 | 28,931,219 | — | $10.1B |
| 2021-Q3 | 181 | 28,383,151 | — | $8.6B |
| 2021-Q2 | 176 | 28,494,215 | — | $8.6B |
| 2021-Q1 | 190 | 28,541,834 | — | $7.8B |
| 2020-Q4 | 172 | 25,923,654 | — | $7.6B |
| 2020-Q3 | 160 | 25,621,218 | — | $6.7B |
| 2020-Q2 | 166 | 26,778,693 | — | $6.1B |
| 2020-Q1 | 143 | 23,403,248 | — | $3.1B |
| 2019-Q4 | 149 | 23,778,169 | — | $3.8B |
| 2019-Q3 | 134 | 22,618,037 | — | $2.6B |
| 2019-Q2 | 134 | 22,499,528 | — | $3.2B |
| 2019-Q1 | 133 | 22,124,793 | — | $2.8B |
| 2018-Q4 | 110 | 20,514,189 | — | $2.0B |
| 2018-Q3 | 106 | 20,762,492 | — | $1.6B |
| 2018-Q2 | 83 | 18,065,447 | — | $1.5B |
| 2018-Q1 | 84 | 16,999,989 | — | $1.4B |
| 2017-Q4 | 63 | 14,457,752 | — | $913M |
| 2017-Q3 | 32 | 6,945,618 | — | $156M |
| 2017-Q2 | 32 | 6,115,327 | — | $129M |
