Vault-13

SEAPORT THERAPEUTICS INC SPTX

COMMON STOCK · Common Stock · CUSIP 81221K108

54 institutional holders
37,408,89637.4m shares reported held*
69.9% of all shares outstanding*
$813.9mreported value*

* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Shares outstanding: 53.5m as of 2026-06-05, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $21.76.

Biggest buyers

ARCH Venture Management, LLC New +6,294,951+6.3m
GENERAL ATLANTIC, L.P. New +6,101,582+6.1m
Sofinnova Investments, Inc. New +3,564,871+3.6m
GOLDMAN SACHS GROUP INC New +2,178,642+2.2m
TRV GP VI, LLC New +2,061,222+2.1m
CANADA PENSION PLAN INVESTMENT BOARD New +1,975,791+2.0m
JPMORGAN CHASE & CO New +1,815,845+1.8m
Foresite Capital Management VI LLC New +1,779,521+1.8m
PRICE T ROWE ASSOCIATES INC /MD/ New +1,308,604+1.3m
FMR LLC New +1,185,100+1.2m

Biggest sellers

None

Major shareholders (over 5%)

Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.

HolderStakeChangeShares Last filed
PureTech LYT, Inc. 13G · exempt (held before listing) new · filed 2026-08-14 31.2% new 16.7m≈ $362.4m 2026-08-14
ARCH Venture Fund XII, L.P. 13D · may seek influence new · filed 2026-05-06
Stated purposeAVF XII and the other Reporting Persons acquired the Common Stock for investment purposes. Depending on market conditions, the continuing evaluation of the business and prospects of the Issuer and other factors, AVF XII and other Reporting Persons may dispose of or acquire additional shares of Common Stock of the Issuer. Except as set forth above, none of the Reporting Persons has any present plans which relate to or would result in the matters set forth in subparagraphs (a) - (j) of Item 4 of Schedule 13D. Full filing
11.9% new 6.3m≈ $136.7m 2026-05-06
GENERAL ATLANTIC, L.P. 13D · may seek influence new · filed 2026-05-11
Stated purposeThe Reporting Persons acquired the common stock reported herein for investment purposes. Consistent with such purposes, the Reporting Persons may engage in communications with, without limitation, one or more shareholders of the Company, management of the Company, one or more members of the board of directors of the Company, and may make suggestions concerning the Company's operations, prospects, business and financial strategies, strategic transactions, assets and liabilities, business and financing alternatives, the composition of the board of directors of the Company and such other matters as the Reporting Persons may deem relevant to their investment in the common stock. The Reporting Persons expect that they will, from time to time, review their investment position in the common stoc… Full filing
11.5% new 6.1m≈ $132.5m 2026-05-11
Zohar Daphne 13G · exempt (held before listing) new · filed 2026-08-05 9.1% new 5.2m≈ $113.5m 2026-08-05
PAUL STEVEN M 13G · exempt (held before listing) new · filed 2026-08-05 6.3% new 3.5m≈ $76.4m 2026-08-05
GOLDMAN SACHS GROUP INC 13G · passive investor new · filed 2026-05-11 5.5% new 2.8m≈ $60.6m 2026-05-11

Insider purchases and sales since 1 Apr 2026

Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.

Officers and directors buying vs selling

Number of people, by quarter (10% owners not included)

BuyingSelling
101Q4 24: 0 buyingQ4 24: 0 sellingQ1 25: 0 buyingQ1 25: 0 sellingQ1 25Q2 25: 0 buyingQ2 25: 0 sellingQ3 25: 0 buyingQ3 25: 0 sellingQ3 25Q4 25: 0 buyingQ4 25: 0 sellingQ1 26: 0 buyingQ1 26: 0 sellingQ1 26Q2 26: 1 buyingQ2 26: 0 sellingQ3 26: 0 buyingQ3 26: 0 sellingQ3 26
Numbers
QuarterBuyingBoughtSellingSoldSold under a plan
Q4 20240—0——
Q1 20250—0——
Q2 20250—0——
Q3 20250—0——
Q4 20250—0——
Q1 20260—0——
Q2 20261$235.8k0——
Q3 20260—0——
DateInsiderTradeSharesPrice ValueTheir holding
2026-06-22 HOMBACH ROBERT J. Director · By Robert Joseph Hombach Revocable Trust Bought 13,000 $18.14 $235.8k13.0k shares new
2026-05-04 CRANDELL KEITH +6 10% owner · By ARCH Venture Fund XII, L.P. Bought 1,100,000 $18.00 $19.8m1.1m shares +21%

Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).

Holders, Q2 2026

#ManagerLocationShares Value% of their portfolioChangeShares change
1 ARCH Venture Management, LLC 12.42% of their portfolio CHICAGO, IL 6,294,9516.3m $136.6m $136.6m 12.42% New
2 GENERAL ATLANTIC, L.P. 4.56% of their portfolio New York, NY 6,101,5826.1m $132.5m $132.5m 4.56% New
3 Sofinnova Investments, Inc. 4.14% of their portfolio Menlo Park, CA 3,564,8713.6m $77.4m $77.4m 4.14% New
4 GOLDMAN SACHS GROUP INC 0.00% of their portfolio NEW YORK, NY 2,178,6422.2m $47.3m $47.3m 0.00% New
5 TRV GP VI, LLC 19.27% of their portfolio Boston, MA 2,061,2222.1m $44.8m $44.8m 19.27% New
6 CANADA PENSION PLAN INVESTMENT BOARD 0.02% of their portfolio TORONTO ONTARIO, A6 1,975,7912.0m $42.9m $42.9m 0.02% New
7 JPMORGAN CHASE & CO 0.00% of their portfolio NEW YORK, NY 1,815,8451.8m $40.9m $40.9m 0.00% New
8 Foresite Capital Management VI LLC 6.02% of their portfolio WEST HOLLYWOOD, CA 1,779,5211.8m $38.7m $38.7m 6.02% New
9 PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio BALTIMORE, MD 1,308,6041.3m $28.4m $28.4m 0.00% New
10 FMR LLC 0.00% of their portfolio BOSTON, MA 1,185,1001.2m $25.7m $25.7m 0.00% New
11 Bellevue Group AG 0.50% of their portfolio ZURICH, V8 1,100,0001.1m $23.9m $23.9m 0.50% New
12 Siren, L.L.C. 0.48% of their portfolio New York, NY 1,095,3161.1m $23.8m $23.8m 0.48% New
13 JENNISON ASSOCIATES LLC 0.01% of their portfolio NEW YORK, NY 1,079,6691.1m $23.5m $23.5m 0.01% New
14 RA CAPITAL MANAGEMENT, L.P. 0.13% of their portfolio BOSTON, MA 700,000700.0k $15.2m $15.2m 0.13% New
15 VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio MALVERN, PA 599,217599.2k $13.0m $13.0m 0.00% New
16 Woodline Partners LP 0.04% of their portfolio San Francisco, CA 586,345586.3k $12.7m $12.7m 0.04% New
17 PERCEPTIVE ADVISORS LLC 0.17% of their portfolio NEW YORK, NY 500,000500.0k $10.9m $10.9m 0.17% New
18 BRAIDWELL LP 0.40% of their portfolio STAMFORD, CT 500,000500.0k $10.9m $10.9m 0.40% New
19 PRINCIPAL FINANCIAL GROUP INC 0.00% of their portfolio DES MOINES, IA 414,672414.7k $9.0m $9.0m 0.00% New
20 Aberdeen Group plc 0.01% of their portfolio EDINBURGH, X0 310,355310.4k $6.7m $6.7m 0.01% New
21 UBS Group AG 0.00% of their portfolio ZURICH, V8 279,184279.2k $6.1m $6.1m 0.00% New
22 BlackRock, Inc. 0.00% of their portfolio New York, NY 229,863229.9k $5.0m $5.0m 0.00% New
23 SEVEN GRAND MANAGERS, LLC 0.20% of their portfolio BRONXVILLE, NY 225,000225.0k $4.9m $4.9m 0.20% New
24 CITADEL ADVISORS LLC 0.00% of their portfolio MIAMI, FL 191,144191.1k $4.2m $4.2m 0.00% New
25 GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio BOSTON, MA 175,866175.9k $3.8m $3.8m 0.00% New
26 Pier Capital, LLC 0.49% of their portfolio STAMFORD, CT 169,985170.0k $3.7m $3.7m 0.49% New
27 AMERIPRISE FINANCIAL INC 0.00% of their portfolio MINNEAPOLIS, MN 131,788131.8k $2.9m $2.9m 0.00% New
28 CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio SAN FRANCISCO, CA 97,69397.7k $2.1m $2.1m 0.00% New
29 VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio MALVERN, PA 87,77287.8k $1.9m $1.9m 0.00% New
30 Pentwater Capital Management LP 0.01% of their portfolio Naples, FL 83,00083.0k $1.8m $1.8m 0.01% New
31 MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio Toronto, A6 82,56582.6k $1.8m $1.8m 0.00% New
32 Alyeska Investment Group, L.P. 0.00% of their portfolio CHICAGO, IL 75,00075.0k $1.6m $1.6m 0.00% New
33 ALPS ADVISORS INC 0.01% of their portfolio Denver, CO 54,32854.3k $1.2m $1.2m 0.01% New
34 TD Asset Management Inc 0.00% of their portfolio Toronto, A6 47,94447.9k $1.0m $1.0m 0.00% New
35 MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio NEW YORK, NY 45,33745.3k $984.7k $984.7k 0.00% New
36 GSA CAPITAL PARTNERS LLP 0.05% of their portfolio LONDON, X0 33,17833.2k $721.0k $721.0k 0.05% New
37 DAFNA Capital Management LLC 0.13% of their portfolio LOS ANGELES, CA 32,40032.4k $703.7k $703.7k 0.13% New
38 NORTHERN TRUST CORP 0.00% of their portfolio CHICAGO, IL 31,80231.8k $690.7k $690.7k 0.00% New
39 ADAR1 Capital Management, LLC 0.03% of their portfolio AUSTIN, TX 26,00026.0k $564.7k $564.7k 0.03% New
40 Ghisallo Capital Management LLC 0.01% of their portfolio BOSTON, MA 25,00025.0k $543.0k $543.0k 0.01% New
41 Burkehill Global Management, LP 0.02% of their portfolio NEW YORK, NY 25,00025.0k $543.0k $543.0k 0.02% New
42 Squarepoint Ops LLC 0.00% of their portfolio NEW YORK, NY 24,75324.8k $537.6k $537.6k 0.00% New
43 HighTower Advisors, LLC 0.00% of their portfolio CHICAGO, IL 16,66616.7k $362.0k $362.0k 0.00% New
44 MORGAN STANLEY 0.00% of their portfolio NEW YORK, NY 11,69211.7k $254.0k $254.0k 0.00% New
45 XTX Topco Ltd 0.00% of their portfolio LONDON, X0 10,98311.0k $238.6k $238.6k 0.00% New
46 Weiss Asset Management LP 0.00% of their portfolio BOSTON, MA 10,00010.0k $217.2k $217.2k 0.00% Not comparable
47 Zimmer Partners, LP 0.01% of their portfolio NEW YORK, NY 10,00010.0k $217.2k $217.2k 0.01% New
48 VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio MALVERN, PA 9,0819.1k $197.2k $197.2k 0.00% New
49 Vanguard Global Advisers, LLC 0.00% of their portfolio MALVERN, PA 7,1597.2k $155.5k $155.5k 0.00% New
50 CITIGROUP INC 0.00% of their portfolio NEW YORK, NY 2,4542.5k $53.3k $53.3k 0.00% New
51 JONES FINANCIAL COMPANIES LLLP 0.00% of their portfolio DES PERES, MO 2,2562.3k $48.3k $48.3k 0.00% New
52 ASSETMARK, INC 0.00% of their portfolio CONCORD, CA 1,4311.4k $31.1k $31.1k 0.00% New
53 BARCLAYS PLC 0.00% of their portfolio LONDON, X0 837837 $18.2k $18.2k 0.00% New
54 Integrated Wealth Concepts LLC 0.00% of their portfolio WALTHAM, MA 3232 $695 $695 0.00% New