Seaport Therapeutics, Inc. (SPTX) Ownership
SPTX ownership summary
as of October 18, 2026- Institutions
- 71.0% of shares outstanding
- Insiders
- 35.14% of shares outstanding
- Shares outstanding
- 53.5M
- Float
- 18.4M shares available to trade
- Short interest
- 7.17% 3.6M shares short
- Days to cover
- 12.95 short interest up 15.9% vs prior month
- Institutions 70.99%
- Insiders 35.14%
SPTX top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | ARCH VENTURE CORP | 11.76% | 6.3M | $112.2M | +6.3M (0.0%) | June 30, 2026 |
| 2 | General Atlantic Llc | 11.40% | 6.1M | $108.8M | +6.1M (0.0%) | June 30, 2026 |
| 3 | Sofinnova Ventures | 6.66% | 3.6M | $63.6M | +3.6M (0.0%) | June 30, 2026 |
| 4 | The Goldman Sachs Group Inc | 4.07% | 2.2M | $38.8M | +2.2M (0.0%) | June 30, 2026 |
| 5 | TRV GP VI, LLC | 3.85% | 2.1M | $36.8M | +2.1M (0.0%) | June 30, 2026 |
| 6 | Canada Pension Plan Investment Board | 3.69% | 2.0M | $35.2M | +2.0M (0.0%) | June 30, 2026 |
| 7 | JPMorgan Chase & Co | 3.39% | 1.8M | $32.4M | +1.8M (0.0%) | June 30, 2026 |
| 8 | Foresite Capital Management VI LLC | 3.32% | 1.8M | $31.7M | +1.8M (0.0%) | June 30, 2026 |
| 9 | T. Rowe Price Associates, Inc. | 2.44% | 1.3M | $23.3M | +1.3M (0.0%) | June 30, 2026 |
| 10 | FMR Inc | 2.21% | 1.2M | $21.1M | +1.2M (0.0%) | June 30, 2026 |
| 11 | Bellevue Group AG | 2.05% | 1.1M | $19.6M | +1.1M (0.0%) | June 30, 2026 |
| 12 | Siren, L.L.C. | 2.05% | 1.1M | $19.5M | +1.1M (0.0%) | June 30, 2026 |
| 13 | Jennison Associates LLC | 2.02% | 1.1M | $19.3M | +1.1M (0.0%) | June 30, 2026 |
| 14 | RA Capital Management, LLC | 1.31% | 700K | $12.5M | +700,000 (0.0%) | June 30, 2026 |
| 15 | Vanguard Capital Management, LLC | 1.12% | 599K | $10.7M | +599,217 (0.0%) | June 30, 2026 |
| 16 | Woodline Partners LP | 1.10% | 586K | $10.5M | +586,345 (0.0%) | June 30, 2026 |
| 17 | Perceptive Advisors LLC | 0.93% | 500K | $8.9M | +500,000 (0.0%) | June 30, 2026 |
| 18 | BRAIDWELL LP | 0.93% | 500K | $8.9M | +500,000 (0.0%) | June 30, 2026 |
| 19 | Principal Financial Group Inc | 0.77% | 415K | $7.4M | +414,672 (0.0%) | June 30, 2026 |
| 20 | Aberdeen Group PLC | 0.58% | 310K | $5.5M | +310,355 (0.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 20 holders added 35.2M shares and 0 cut 0.
SPTX top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | T. Rowe Price Health Sciences | 2.14% | 1.1M | $20.4M | +105,400 (+10.1%) | August 31, 2026 |
| 2 | JPMorgan Small Cap Growth A | 1.55% | 828K | $14.8M | −12,949 (−1.5%) | August 31, 2026 |
| 3 | PGIM Jennison Health Sciences Z | 0.82% | 439K | $7.8M | — | August 31, 2026 |
| 4 | Vanguard MStar Total Stk Mkt Idx Invest | 0.80% | 426K | $7.6M | — | August 31, 2026 |
| 5 | Fidelity Growth Company Fund | 0.79% | 424K | $7.6M | +73,500 (+21.0%) | August 31, 2026 |
| 6 | iShares Russell 2000 ETF | 0.66% | 355K | $6.3M | +14,403 (+4.2%) | September 30, 2026 |
| 7 | JPMorgan Small Cap Blend A | 0.50% | 265K | $4.7M | −6,154 (−2.3%) | August 31, 2026 |
| 8 | Fidelity Blue Chip Growth | 0.44% | 236K | $4.2M | — | August 31, 2026 |
| 9 | Principal SmallCap R5 | 0.28% | 150K | $2.7M | −31,387 (−17.3%) | August 31, 2026 |
| 10 | Fidelity Growth Company K6 | 0.22% | 120K | $2.1M | +21,000 (+21.3%) | August 31, 2026 |
| 11 | Multi-Manager Small Cap Eq Strat Inst | 0.21% | 111K | $2.0M | −20,349 (−15.4%) | August 31, 2026 |
| 12 | Fidelity Series Growth Company | 0.20% | 104K | $1.9M | +18,900 (+22.1%) | August 31, 2026 |
| 13 | JPM US Small Cap Growth A dist USD | 0.18% | 98K | $1.7M | — | August 31, 2026 |
| 14 | AdvisorShares Psychedelics ETF | 0.18% | 94K | $1.7M | — | September 30, 2026 |
| 15 | abrdn Healthcare Opportunities | 0.17% | 89K | $1.6M | — | August 31, 2026 |
| 16 | abrdn Healthcare Investors | 0.16% | 88K | $1.6M | −21,601 (−19.7%) | August 31, 2026 |
| 17 | TD Health Sciences - I | 0.16% | 86K | $1.5M | — | June 30, 2026 |
| 18 | iShares Russell 2000 Growth ETF | 0.15% | 78K | $1.4M | −99 (−0.1%) | September 30, 2026 |
| 19 | Schwab US Small-Cap ETF™ | 0.14% | 77K | $1.4M | +45 (+0.1%) | September 30, 2026 |
| 20 | Fidelity Extended Market Index | 0.13% | 71K | $1.3M | −384 (−0.5%) | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
Who owns SPTX
Institutional investors own 71.0% of Seaport Therapeutics's shares and insiders 35.14%. The largest holder is ARCH VENTURE CORP with 11.76% of the shares (6.3M), as of June 30, 2026. Among the top 20 institutions, 20 added shares and 0 reduced their stake in the latest filings. Short interest is 7.17% of the float, or 12.95 days of average trading volume.
Related: SPTX analyst forecast, SPTX key metrics. See the SPTX stock overview for the latest quote and news.
SPTX ownership FAQ
Who owns the most Seaport Therapeutics stock?
The largest shareholders of Seaport Therapeutics are ARCH VENTURE CORP (11.76%), General Atlantic Llc (11.40%), Sofinnova Ventures (6.66%), The Goldman Sachs Group Inc (4.07%), TRV GP VI, LLC (3.85%).
What percentage of Seaport Therapeutics is owned by institutions?
Institutions hold 71.0% of Seaport Therapeutics's shares outstanding; insiders hold 35.14%.
Which funds own Seaport Therapeutics?
The largest fund holders of Seaport Therapeutics are T. Rowe Price Health Sciences (2.14%), JPMorgan Small Cap Growth A (1.55%), PGIM Jennison Health Sciences Z (0.82%), Vanguard MStar Total Stk Mkt Idx Invest (0.80%), Fidelity Growth Company Fund (0.79%).
What is Seaport Therapeutics's short interest?
3.6M shares of Seaport Therapeutics were sold short, 7.17% of the float; at the average daily volume it would take 12.95 days to cover.
How many shares of Seaport Therapeutics are outstanding?
Seaport Therapeutics has 53.5M shares outstanding, of which 18.4M are in the public float.