% 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 78,536,412 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 ABVX 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 | TCG Crossover Management, LLC | 6,481,0856.5M | $722M | — | TRIM -9% |
| 2 | UBS Group AG | 4,547,4064.5M | $506M | — | ADD 3% |
| 3 | Darwin Global Management, Ltd. | 3,468,6573.5M | $352M | — | ADD 9% |
| 4 | MORGAN STANLEY | 1,704,9581.7M | $190M | — | TRIM -46% |
| 5 | Vestal Point Capital, LP | 1,500,0001.5M | $167M | — | TRIM -21% |
| 6 | Caligan Partners LP | 1,461,9241.5M | $163M | — | — |
| 7 | ADAR1 Capital Management, LLC | 1,394,0191.4M | $155M | — | ADD 6% |
| 8 | WESTFIELD CAPITAL MANAGEMENT CO LP | 1,322,9381.3M | $147M | — | ADD 31% |
| 9 | FMR LLC | 1,286,3731.3M | $143M | — | TRIM -6% |
| 10 | Helikon Investments Ltd | 1,013,3241.0M | $113M | — | NEW |
| 11 | Eversept Partners, LP | 934,423934,423 | $104M | — | ADD 42% |
| 12 | JANUS HENDERSON GROUP PLC | 878,829878,829 | $98M | — | ADD 32% |
| 13 | BAKER BROS. ADVISORS LP | 875,796875,796 | $98M | — | — |
| 14 | LORD, ABBETT & CO. LLC | 854,920854,920 | $95M | — | — |
| 15 | Paradigm Biocapital Advisors LP | 772,473772,473 | $86M | — | TRIM -46% |
| 16 | Nationale-Nederlanden Powszechne Towarzystwo Emerytalne S.A. | 765,915765,915 | $85M | — | ADD 11% |
| 17 | Cormorant Asset Management, LP | 760,000760,000 | $85M | — | TRIM -44% |
| 18 | BANK OF AMERICA CORP /DE/ | 735,729735,729 | $82M | — | ADD 41% |
| 19 | PRICE T ROWE ASSOCIATES INC /MD/ | 691,670691,670 | $77M | — | ADD 6% |
| 20 | Octagon Capital Advisors LP | 677,000677,000 | $75M | — | TRIM -10% |
| 21 | Logos Global Management LP | 675,000675,000 | $75M | — | ADD 69% |
| 22 | Point72 Asset Management, L.P. | 637,736637,736 | $71M | — | TRIM -74% |
| 23 | Ensign Peak Advisors, Inc | 631,838631,838 | $70M | — | ADD 22% |
| 24 | STEMPOINT CAPITAL LP | 627,582627,582 | $70M | — | ADD 60% |
| 25 | MILLENNIUM MANAGEMENT LLC | 605,992605,992 | $67M | — | TRIM -18% |
| 26 | Artia Global Partners LP | 600,747600,747 | $67M | — | — |
| 27 | JPMORGAN CHASE & CO | 635,066635,066 | $64M | — | ADD 39% |
| 28 | CITADEL ADVISORS LLC | 544,338544,338 | $61M | — | TRIM -3% |
| 29 | Saturn V Capital Management LP | 542,696542,696 | $60M | — | TRIM -16% |
| 30 | BOOTHBAY FUND MANAGEMENT, LLC | 472,961472,961 | $53M | — | TRIM -7% |
| 31 | First Turn Management, LLC | 465,869465,869 | $52M | — | ADD 22% |
| 32 | ORBIMED ADVISORS LLC | 465,700465,700 | $52M | — | ADD 27% |
| 33 | Aberdeen Group plc | 431,241431,241 | $48M | — | — |
| 34 | BlackRock, Inc. | 427,335427,335 | $48M | — | TRIM -2% |
| 35 | Affinity Asset Advisors, LLC | 405,000405,000 | $45M | — | TRIM -20% |
| 36 | ADAGE CAPITAL PARTNERS GP, L.L.C. | 400,539400,539 | $45M | — | TRIM -27% |
| 37 | FRANKLIN RESOURCES INC | 382,830382,830 | $43M | — | TRIM -15% |
| 38 | SUSQUEHANNA INTERNATIONAL GROUP, LLP | 381,282381,282 | $42M | — | TRIM -49% |
| 39 | GOLDMAN SACHS GROUP INC | 348,797348,797 | $39M | — | ADD 32% |
| 40 | PERCEPTIVE ADVISORS LLC | 328,884328,884 | $37M | — | TRIM -28% |
| 41 | EVENTIDE ASSET MANAGEMENT, LLC | 320,576320,576 | $36M | — | TRIM -2% |
| 42 | PRINCIPAL FINANCIAL GROUP INC | 312,274312,274 | $35M | — | ADD 43% |
| 43 | SILVERARC CAPITAL MANAGEMENT, LLC | 302,530302,530 | $34M | — | TRIM -28% |
| 44 | Holocene Advisors, LP | 258,657258,657 | $29M | — | — |
| 45 | Vivo Capital, LLC | 239,539239,539 | $27M | — | TRIM -33% |
| 46 | Woodline Partners LP | 225,892225,892 | $25M | — | — |
| 47 | Balyasny Asset Management L.P. | 213,689213,689 | $24M | — | TRIM -40% |
| 48 | JENNISON ASSOCIATES LLC | 210,534210,534 | $23M | — | ADD 65% |
| 49 | READYSTATE ASSET MANAGEMENT LP | 202,022202,022 | $22M | — | ADD 111% |
| 50 | Boxer Capital Management, LLC | 200,000200,000 | $22M | — | ADD 60% |
| 51 | Creek Drive Management Group LLC | 155,000155,000 | $17M | — | ADD 50% |
| 52 | Evergreen Quality Fund GP, Ltd. | 144,300144,300 | $16M | — | TRIM -36% |
| 53 | ExodusPoint Capital Management, LP | 140,262140,262 | $16M | — | TRIM -35% |
| 54 | Hudson Bay Capital Management LP | 139,379139,379 | $16M | — | TRIM -33% |
| 55 | Nantahala Capital Management, LLC | 137,237137,237 | $15M | — | TRIM -10% |
| 56 | Sio Capital Management, LLC | 135,800135,800 | $15M | — | ADD 215% |
| 57 | Squadron Capital Management LLC | 130,000130,000 | $14M | — | TRIM -10% |
| 58 | NAN FUNG TRINITY (HK) LTD | 128,940128,940 | $14M | — | ADD 14% |
| 59 | Apis Capital Advisors, LLC | 128,800128,800 | $14M | — | ADD 45% |
| 60 | Invesco Ltd. | 126,420126,420 | $14M | — | — |
| 61 | Patient Square Capital LP | 121,245121,245 | $14M | — | TRIM -7% |
| 62 | HighVista Strategies LLC | 113,254113,254 | $13M | — | ADD 57% |
| 63 | TimesSquare Capital Management, LLC | 109,183109,183 | $12M | — | TRIM -16% |
| 64 | FEDERATED HERMES, INC. | 108,200108,200 | $12M | — | — |
| 65 | MPM BIOIMPACT LLC | 107,268107,268 | $12M | — | ADD 90% |
| 66 | IMC-Chicago, LLC | 106,143106,143 | $12M | — | ADD 543% |
| 67 | Prosight Management, LP | 105,000105,000 | $12M | — | ADD 518% |
| 68 | FINDELL CAPITAL MANAGEMENT LLC | 105,000105,000 | $12M | — | ADD 119% |
| 69 | TUDOR INVESTMENT CORP ET AL | 101,611101,611 | $11M | — | ADD 256% |
| 70 | Pictet Asset Management Holding SA | 103,545103,545 | $11M | — | TRIM -17% |
| 71 | Kite Lake Capital Management (UK) LLP | 100,000100,000 | $11M | — | NEW |
| 72 | SEI INVESTMENTS CO | 94,22094,220 | $10M | — | ADD 8% |
| 73 | JANE STREET GROUP, LLC | 94,14194,141 | $10M | — | TRIM -78% |
| 74 | BARCLAYS PLC | 90,77590,775 | $10M | — | TRIM -71% |
| 75 | Nicholas Investment Partners, LP | 90,20690,206 | $10M | — | ADD 9% |
| 76 | AMERIPRISE FINANCIAL INC | 83,03183,031 | $9M | — | ADD 23% |
| 77 | ODDO BHF ASSET MANAGEMENT SAS | 81,49681,496 | $9M | — | ADD 3% |
| 78 | ANDERA PARTNERS | 78,12578,125 | $9M | — | — |
| 79 | Davern Capital Partners, LP | 78,12578,125 | $9M | — | ADD 61% |
| 80 | Velan Capital Investment Management LP | 77,00077,000 | $9M | — | ADD 15% |
| 81 | LMR Partners LLP | 76,55276,552 | $9M | — | TRIM -19% |
| 82 | LPL Financial LLC | 75,36675,366 | $8M | — | ADD 20% |
| 83 | DIADEMA PARTNERS LP | 75,94475,944 | $8M | — | — |
| 84 | Voleon Capital Management LP | 73,72673,726 | $8M | — | TRIM -30% |
| 85 | ACT CAPITAL MANAGEMENT, LLC | 70,90070,900 | $8M | — | ADD 11% |
| 86 | TD Asset Management Inc | 65,54865,548 | $7M | — | ADD 3% |
| 87 | Russell Investments Group, Ltd. | 65,27365,273 | $7M | — | — |
| 88 | ENVESTNET ASSET MANAGEMENT INC | 59,20959,209 | $7M | — | ADD 30% |
| 89 | Centiva Capital, LP | 57,15057,150 | $6M | — | NEW |
| 90 | SAMSARA BIOCAPITAL, LLC | 56,58156,581 | $6M | — | TRIM -25% |
| 91 | Ikarian Capital, LLC | 57,63557,635 | $6M | — | TRIM -72% |
| 92 | K2 PRINCIPAL FUND, L.P. | 53,74153,741 | $6M | — | ADD 139% |
| 93 | GEODE CAPITAL MANAGEMENT, LLC | 51,31251,312 | $6M | — | ADD 3% |
| 94 | D. E. Shaw & Co., Inc. | 50,55050,550 | $6M | — | ADD 187% |
| 95 | SEVEN GRAND MANAGERS, LLC | 50,00050,000 | $6M | — | NEW |
| 96 | BNP PARIBAS ASSET MANAGEMENT Holding S.A. | 49,51649,516 | $6M | — | ADD 100% |
| 97 | Trexquant Investment LP | 48,74948,749 | $5M | — | ADD 11% |
| 98 | Catalio Capital Management, LP | 47,19347,193 | $5M | — | TRIM -52% |
| 99 | Erste Asset Management GmbH | 50,00050,000 | $5M | — | — |
| 100 | HRT FINANCIAL LP | 45,37145,371 | $5M | — | NEW |
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 |
|---|---|---|---|---|---|---|---|
| TCG Crossover Management, LLC | 6.1M | 6.1M | 6.1M | 7.1M | 7.1M | 6.5M | $722M |
| UBS Group AG | 175K | 163K | 168K | 4.5M | 4.4M | 4.5M | $506M |
| Darwin Global Management, Ltd. | — | — | — | 3.2M | 3.2M | 3.5M | $352M |
| MORGAN STANLEY | 479K | 497K | 475K | 1.5M | 3.2M | 1.7M | $190M |
| Vestal Point Capital, LP | — | — | — | 1.0M | 1.9M | 1.5M | $167M |
| Caligan Partners LP | 752K | 1.3M | 1.7M | 1.5M | 1.5M | 1.5M | $163M |
| ADAR1 Capital Management, LLC | 1.5M | 2.2M | 3.1M | 1.4M | 1.3M | 1.4M | $155M |
| WESTFIELD CAPITAL MANAGEMENT CO LP | — | — | — | — | 1.0M | 1.3M | $147M |
| FMR LLC | — | — | — | 1.4M | 1.4M | 1.3M | $143M |
| Helikon Investments Ltd | — | — | — | — | — | 1.0M | $113M |
| Eversept Partners, LP | — | — | — | 426K | 658K | 934K | $104M |
| JANUS HENDERSON GROUP PLC | — | — | — | 355K | 668K | 879K | $98M |
| BAKER BROS. ADVISORS LP | — | — | — | 876K | 876K | 876K | $98M |
| LORD, ABBETT & CO. LLC | — | — | — | 337K | 850K | 855K | $95M |
| Paradigm Biocapital Advisors LP | — | — | — | 1.6M | 1.4M | 772K | $86M |
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.
| Quarter | Holders | Shares held | % shares out | Value held |
|---|---|---|---|---|
| 2026-Q1 | 252 | 50,351,364 | — | $5.6B |
| 2025-Q4 | 247 | 56,311,702 | — | $7.6B |
| 2025-Q3 | 165 | 51,964,814 | — | $4.4B |
| 2025-Q2 | 43 | 30,664,346 | — | $235M |
| 2025-Q1 | 46 | 31,761,546 | — | $199M |
| 2024-Q4 | 48 | 29,861,066 | — | $219M |
| 2024-Q3 | 40 | 27,383,884 | — | $313M |
| 2024-Q2 | 38 | 29,084,544 | — | $385M |
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.
“Item 4 of the Schedule 13D is hereby amended and supplemented as follows: SC sold the amounts of ADS and Ordinary Shares on the date and at the prices set forth below in open market transactions on NASDAQ and Euronext. All daily sales of the shares were sold in multiple transactions at varying prices. The Reporting Persons undertake to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number”
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 | |
|---|---|---|---|
| Helikon Investments Ltd | +1,013,324 | $113M | OPEN |
| WESTFIELD CAPITAL MANAGEMENT CO LP | +312,972 | $35M | ADD |
| Darwin Global Management, Ltd. | +290,156 | $32M | ADD |
| Eversept Partners, LP | +276,589 | $31M | ADD |
| Logos Global Management LP | +275,000 | $31M | ADD |
| Biggest sellers | Δ shares | Δ value | |
|---|---|---|---|
| Point72 Asset Management, L.P. | −1,771,418 | $197M | TRIM |
| MORGAN STANLEY | −1,447,036 | $161M | TRIM |
| DEUTSCHE BANK AG\ | −764,899 | $85M | CLOSE |
| Paradigm Biocapital Advisors LP | −645,000 | $72M | TRIM |
| TCG Crossover Management, LLC | −630,511 | $70M | 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).
| 2024-Q1 | 36 | 24,558,938 | — | $351M |
| 2023-Q4 | 30 | 22,703,842 | — | $243M |
