Abivax S.a.: which funds bought and sold

Institutions that bought and sold Abivax shares in Q2 2026, from the holdings they reported to the SEC on Form 13F for March 31, 2026 and June 30, 2026.

Between March 31, 2026 and June 30, 2026, 184 institutions that filed 13F reports for both quarters added to or opened positions in Abivax, and 139 cut or closed them. Together they added a net 2.5M shares, +5.1% on what they held at the start of the quarter. Active managers and hedge funds on our list were net buyers of 1.2M shares (+7.1%); index fund managers were net buyers of 150K shares (+30.8%). 86 opened a new position and 39 sold out entirely.

Bought, Q2 2026 184 institutions, 86 of them new holders Sold, Q2 2026 139 institutions, 39 of them sold out

Net change, all compared +2.5M shares (+5.1%)

Net change, active managers +1.2M shares (+7.1%), 32 bought, 27 sold

Buyers versus sellers

institutions compared, 336

184 bought 13 139 sold

Active managers and hedge funds 32 bought · 27 sold · +1.2M

Index fund managers 4 bought · 2 sold · +150K

Other institutions 148 bought · 110 sold · +1.2M

Biggest buyers

by change in shares held

Biggest buyers
Institution	Change in shares	Shares June 30, 2026	Value
Helikon Investments Ltd	+1.8M +175.0%	2.8M	$371M
RA Capital Management, L.P. Hedge fund	+1.1M New position	1.1M	$151M
Citadel Advisors LLC Hedge fund	+894K +164.2%	1.4M	$192M
Vestal Point Capital, LP Hedge fund	+849K +56.6%	2.3M	$313M
Susquehanna International Group, LLP	+673K +176.4%	1.1M	$140M
Siren, L.L.C.	+576K New position	576K	$76.8M
Goldman Sachs Group Inc	+444K +127.3%	793K	$106M
ADAR1 Capital Management, LLC Hedge fund	+411K +29.5%	1.8M	$240M
Summit Partners Public Asset Management, LLC	+410K New position	410K	$54.6M
Boxer Capital Management, LLC Hedge fund	+405K +202.5%	605K	$80.6M
Balyasny Asset Management L.P. Hedge fund	+390K +182.6%	604K	$80.5M
Pictet Asset Management Holding SA	+389K +375.2%	492K	$65.6M
Logos Global Management LP Hedge fund	+349K +51.7%	1.0M	$136M
Octagon Capital Advisors LP	+316K +46.7%	993K	$132M
Melqart Asset Management (UK) Ltd	+307K New position	307K	$40.9M
Ikarian Capital, LLC	+271K +470.2%	329K	$43.4M
Two Seas Capital LP Hedge fund	+245K New position	245K	$32.6M
Bank Of America Corp	+236K +32.0%	971K	$129M
Mpm Bioimpact LLC	+229K +213.6%	336K	$44.8M
HRT Financial LP	+225K +496.4%	271K	$36.1M

Biggest buyers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
RA Capital Management, L.P. Hedge fund	+1.1M New position	1.1M	$151M
Citadel Advisors LLC Hedge fund	+894K +164.2%	1.4M	$192M
Vestal Point Capital, LP Hedge fund	+849K +56.6%	2.3M	$313M
ADAR1 Capital Management, LLC Hedge fund	+411K +29.5%	1.8M	$240M
Boxer Capital Management, LLC Hedge fund	+405K +202.5%	605K	$80.6M
Balyasny Asset Management L.P. Hedge fund	+390K +182.6%	604K	$80.5M
Logos Global Management LP Hedge fund	+349K +51.7%	1.0M	$136M
Two Seas Capital LP Hedge fund	+245K New position	245K	$32.6M
Holocene Advisors, LP Hedge fund	+160K +61.9%	419K	$55.8M
Nantahala Capital Management, LLC Hedge fund	+130K +94.9%	268K	$35.6M

Biggest sellers

by change in shares held

Biggest sellers
Institution	Change in shares	Shares June 30, 2026	Value
UBS Group AG	−2.7M −59.4%	1.8M	$246M
FMR LLC Active manager	−1.1M −85.1%	192K	$25.5M
Baker Bros. Advisors LP Hedge fund	−876K Sold out	0	—
Lord, Abbett & Co. LLC	−845K −98.9%	9,500	$1.3M
Paradigm Biocapital Advisors LP	−772K Sold out	0	—
Point72 Asset Management, L.P. Hedge fund	−633K −99.2%	5,028	$670,031
Jpmorgan Chase & Co	−629K −99.1%	5,717	$549,786
Tcg Crossover Management, LLC	−473K −7.3%	6.0M	$801M
Price T Rowe Associates Inc Active manager	−391K −56.6%	300K	$40M
Adage Capital Partners Gp, L.L.C. Hedge fund	−374K −93.4%	27K	$3.5M
Millennium Management LLC Hedge fund	−372K −61.4%	234K	$31.1M
Stempoint Capital LP	−344K −54.8%	284K	$37.8M
Morgan Stanley	−273K −16.0%	1.4M	$191M
Perceptive Advisors LLC Hedge fund	−255K −77.5%	74K	$9.9M
Evergreen Quality Fund Gp, Ltd.	−144K Sold out	0	—
Hudson Bay Capital Management LP Hedge fund	−139K Sold out	0	—
Sio Capital Management, LLC	−136K Sold out	0	—
Silverarc Capital Management, LLC	−133K −43.9%	170K	$22.6M
Squadron Capital Management LLC	−130K Sold out	0	—
Ensign Peak Advisors, Inc	−127K −20.2%	504K	$67.2M

Biggest sellers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
FMR LLC Active manager	−1.1M −85.1%	192K	$25.5M
Baker Bros. Advisors LP Hedge fund	−876K Sold out	0	—
Point72 Asset Management, L.P. Hedge fund	−633K −99.2%	5,028	$670,031
Price T Rowe Associates Inc Active manager	−391K −56.6%	300K	$40M
Adage Capital Partners Gp, L.L.C. Hedge fund	−374K −93.4%	27K	$3.5M
Millennium Management LLC Hedge fund	−372K −61.4%	234K	$31.1M
Perceptive Advisors LLC Hedge fund	−255K −77.5%	74K	$9.9M
Hudson Bay Capital Management LP Hedge fund	−139K Sold out	0	—
Exoduspoint Capital Management, LP Hedge fund	−109K −77.7%	31K	$4.2M
Cormorant Asset Management, LP Hedge fund	−85K −11.2%	675K	$90M

New positions

largest by value

Institution	Shares	Value June 30, 2026
RA Capital Management, L.P.Hedge fund	1.1M	$151M
Siren, L.L.C.	576K	$76.8M
Summit Partners Public Asset Management, LLC	410K	$54.6M
Melqart Asset Management (UK) Ltd	307K	$40.9M
Two Seas Capital LPHedge fund	245K	$32.6M
Great Point Partners LLC	204K	$27.2M
Western Standard LLC	200K	$26.7M
Focus Partners Wealth	162K	$21.6M
Apeiron Capital Ltd	131K	$17.4M
Wellington Management Group LLPActive manager	123K	$16.4M

Sold out

largest by value

Institution	Shares	Value March 31, 2026
Baker Bros. Advisors LPHedge fund	876K	$97.5M
Paradigm Biocapital Advisors LP	772K	$86M
Evergreen Quality Fund Gp, Ltd.	144K	$16.1M
Hudson Bay Capital Management LPHedge fund	139K	$15.5M
Sio Capital Management, LLC	136K	$15.1M
Squadron Capital Management LLC	130K	$14.5M
Nicholas Investment Partners, LP	90K	$10M
Davern Capital Partners, LP	78K	$8.7M
Militia Capital Management LLC	51K	$5.7M
Trexquant Investment LPHedge fund	49K	$5.4M

Who holds the shares

13F holdings at June 30, 2026

Institutions reporting: 301
Ten largest holders: 45.0%
Index fund managers: 1.2%
Active managers and hedge funds: 32.2%

Buying and selling by type of institution, March 31, 2026 to June 30, 2026
Type	Bought	Sold	New	Sold out	Net change in shares	Net %
Active managers and hedge funds	32	27	12	7	+1.2M	+7.1%
Index fund managers	4	2	1	0	+150K	+30.8%
Other institutions	148	110	73	32	+1.2M	+3.6%

Active managers and hedge funds: a list we maintain of about 400 well-known stock-picking firms and hedge funds, matched by SEC registration number (CIK) and checked against the filer names each quarter. Index fund managers: the large index houses, such as BlackRock, Vanguard, State Street, Geode and Northern Trust. Every other filer (banks, brokers, wealth managers, pension funds, insurers and firms not on the list) counts as another institution. A firm that files under several SEC registrations appears once for each.

What these filings can and cannot tell you

Form 13F lists the long positions in US-listed shares held by investment managers with more than $100 million in such holdings. Managers file it up to 45 days after each quarter ends, so this page shows what funds held at the end of each quarter, not what they are doing now: a position may have changed since. Short positions, most derivatives and smaller managers are not included, and a cut can mean a fund lost clients or rebalanced rather than a view on Abivax.

Only managers that filed a holdings report for both quarters are compared (336 here). 7 other holders are left out: first-time or late filers, firms that changed their SEC registration, and filings that withheld positions under confidential treatment, any of which would otherwise look like a new position or a sale. Figures are as reported by each manager in the SEC's quarterly 13F data sets; option positions are excluded.

← Back to Abivax S.a. · Insiders · Politicians