Seaport Therapeutics, Inc.: which funds bought and sold

Institutions that bought and sold Seaport Therapeutics 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, 53 institutions that filed 13F reports for both quarters added to or opened positions in Seaport Therapeutics, and 0 cut or closed them. Together they added a net 37.4M shares, — on what they held at the start of the quarter. Active managers and hedge funds on our list were net buyers of 6.4M shares; index fund managers were net buyers of 1.2M shares. 53 opened a new position and 0 sold out entirely.

Bought, Q2 2026 53 institutions, 53 of them new holders Sold, Q2 2026 0 institutions, 0 of them sold out

Net change, all compared +37.4M shares (—)

Net change, active managers +6.4M shares (—), 16 bought, 0 sold

Buyers versus sellers

institutions compared, 53

53 bought 0 sold

Active managers and hedge funds 16 bought · 0 sold · +6.4M

Index fund managers 7 bought · 0 sold · +1.2M

Other institutions 30 bought · 0 sold · +29.8M

Biggest buyers

by change in shares held

Biggest buyers
Institution	Change in shares	Shares June 30, 2026	Value
Arch Venture Management, LLC	+6.3M New position	6.3M	$137M
General Atlantic, L.P.	+6.1M New position	6.1M	$133M
Sofinnova Investments, Inc.	+3.6M New position	3.6M	$77.4M
Goldman Sachs Group Inc	+2.2M New position	2.2M	$47.3M
Trv Gp Vi, LLC	+2.1M New position	2.1M	$44.8M
Canada Pension Plan Investment Board	+2.0M New position	2.0M	$42.9M
Jpmorgan Chase & Co	+1.8M New position	1.8M	$40.9M
Foresite Capital Management Vi LLC	+1.8M New position	1.8M	$38.7M
Price T Rowe Associates Inc Active manager	+1.3M New position	1.3M	$28.4M
FMR LLC Active manager	+1.2M New position	1.2M	$25.7M
Bellevue Group AG	+1.1M New position	1.1M	$23.9M
Siren, L.L.C.	+1.1M New position	1.1M	$23.8M
Jennison Associates LLC Active manager	+1.1M New position	1.1M	$23.5M
RA Capital Management, L.P. Hedge fund	+700K New position	700K	$15.2M
Vanguard Capital Management LLC Index funds	+599K New position	599K	$13M
Woodline Partners LP Hedge fund	+586K New position	586K	$12.7M
Braidwell LP Hedge fund	+500K New position	500K	$10.9M
Perceptive Advisors LLC Hedge fund	+500K New position	500K	$10.9M
Principal Financial Group Inc	+415K New position	415K	$9M
Aberdeen Group PLC	+310K New position	310K	$6.7M

Biggest buyers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
Price T Rowe Associates Inc Active manager	+1.3M New position	1.3M	$28.4M
FMR LLC Active manager	+1.2M New position	1.2M	$25.7M
Jennison Associates LLC Active manager	+1.1M New position	1.1M	$23.5M
RA Capital Management, L.P. Hedge fund	+700K New position	700K	$15.2M
Woodline Partners LP Hedge fund	+586K New position	586K	$12.7M
Braidwell LP Hedge fund	+500K New position	500K	$10.9M
Perceptive Advisors LLC Hedge fund	+500K New position	500K	$10.9M
Citadel Advisors LLC Hedge fund	+191K New position	191K	$4.2M
Pentwater Capital Management LP Hedge fund	+83K New position	83K	$1.8M
Alyeska Investment Group, L.P. Hedge fund	+75K New position	75K	$1.6M

Biggest sellers

by change in shares held

Biggest sellers
Institution	Change in shares	Shares June 30, 2026	Value
No institution cut its holding.

Biggest sellers, active managers and hedge funds
Institution	Change in shares	Shares June 30, 2026	Value
None of the active managers on our list.

New positions

largest by value

Institution	Shares	Value June 30, 2026
Arch Venture Management, LLC	6.3M	$137M
General Atlantic, L.P.	6.1M	$133M
Sofinnova Investments, Inc.	3.6M	$77.4M
Goldman Sachs Group Inc	2.2M	$47.3M
Trv Gp Vi, LLC	2.1M	$44.8M
Canada Pension Plan Investment Board	2.0M	$42.9M
Jpmorgan Chase & Co	1.8M	$40.9M
Foresite Capital Management Vi LLC	1.8M	$38.7M
Price T Rowe Associates IncActive manager	1.3M	$28.4M
FMR LLCActive manager	1.2M	$25.7M

Sold out

largest by value

Institution	Shares	Value March 31, 2026
No institution sold its whole holding.

Who holds the shares

13F holdings at June 30, 2026

Institutions reporting: 54
Ten largest holders: 75.6%
Index fund managers: 3.3%
Active managers and hedge funds: 17.0%

Buying and selling by type of institution, March 31, 2026 to June 30, 2026
Type	Bought	New	Net change in shares	Net %
Active managers and hedge funds	16	16	+6.4M	—
Index fund managers	7	7	+1.2M	—
Other institutions	30	30	+29.8M	—

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 Seaport Therapeutics.

Only managers that filed a holdings report for both quarters are compared (53 here). 1 other holder is 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.

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