Seaport Therapeutics (SPTX): which funds own it
A 13F shows the portfolio at quarter-end and is filed up to 45 days later: these are not real-time positions and they may have changed.
Sections with a free account
3 concentrated managers hold it (+3 vs last quarter) with a median weight of 0.1%. 2 officers or directors bought in 6 months.
Who owns Seaport Therapeutics?
Holders reporting more than 5% of the shares to the SEC (Schedules 13D/13G): PureTech Health, 31.2% (13G filed Aug 14, 2026), ARCH Venture Fund XII, 11.9% (13D filed May 6, 2026), General Atlantic, 11.5% (13D filed May 11, 2026), Zohar Daphne, 9.1% (13G filed Aug 5, 2026) and Paul Steven M, 6.3% (13G filed Aug 5, 2026). ARCH Venture Partners XII, L.P. is listed on Form 4 filings as an owner of more than 10%. As of Jun 30, 2026, the largest holders reported on Form 13F were ARCH Venture Management (11.8% of the shares), General Atlantic (11.4%) and Sofinnova Investments (6.7%).
Which institutions hold the most Seaport Therapeutics shares?
Per Form 13F filings as of Jun 30, 2026, as a share of all shares outstanding:
- 1. ARCH Venture Management: 11.8%
- 2. General Atlantic: 11.4%
- 3. Sofinnova Investments: 6.7%
- 4. Goldman Sachs Group: 4.1%
- 5. Trv Gp Vi: 3.9%
- 6. Canada Pension Plan Investment Board: 3.7%
- 7. JPMorgan Chase: 3.4%
- 8. Foresite Capital Management VI: 3.3%
- 9. Price T Rowe Associates: 2.4%
- 10. FMR: 2.2%
How much of Seaport Therapeutics do institutions own?
The 54 institutions that file 13F reported 70.0% of the shares as of Jun 30, 2026.
Sources:13G by PureTech Health (Aug 14, 2026) ↗13D by ARCH Venture Fund XII (May 6, 2026) ↗13D by General Atlantic (May 11, 2026) ↗13G by Zohar Daphne (Aug 5, 2026) ↗13G by Paul Steven M (Aug 5, 2026) ↗All of the company's proxy statements on EDGAR ↗
13F percentages divide the shares each institution reports by the shares outstanding on the cover of the company's latest report before the quarter end (Jun 5, 2026). Entities of the same group file separately and are not added up. We hold 13D and 13G filings made since Dec 23, 2024: a holder above 5% that has not filed since then does not appear here.
Quarter flow (concentrated managers)
Change in managers (0 → 3): 3 opened · 0 exited = +3
Net flow in the quarter: +$93.3M (+4.3 M shares) · bought $93.3M and sold $0Shares concentrated managers added minus those they cut, valued at the 13F quarter-end implied price, not each trade's price. It is a different measure from the change in managers: the two can have opposite signs.
Concentrated managers holding it
- Sofinnova InvestmentsNewly listed$77.4M4.1%+3.9 pp
- RA Capital ManagementNewly listed$15.2M0.1%+0.1 pp
- DAFNA Capital ManagementNewly listed$704K0.1%+0.1 pp
Up to 15, sorted by position value. The percentage is the weight in each manager's portfolio.
Other relevant holders
Filers with $100M or more in the stock that do not count as concentrated managers because of their type: they are left out of the counts, the consensus and the accumulation.
- ARCH Venture ManagementPrivate equity or venture capital$137M12.4%
- General AtlanticPrivate equity or venture capital$133M4.6%
Largest holders of SPTX (all 13F filers)
- ARCH Venture Management6.3 MPrivate equity or venture capital+6.3 M
- General Atlantic6.1 MPrivate equity or venture capital+6.1 M
- Sofinnova Investmentsconcentrated3.6 MInvestment firm+3.6 M
- Goldman Sachs Group2.2 MBank or trading desk+2.2 M
- TRV Gp VI2.1 MSingle-position portfolio+2.1 M
- Canada Pension Plan Investment Board2.0 MPension or sovereign fund+2.0 M
- JPMorgan Chase1.8 MBank or trading desk+1.8 M
- Foresite Capital Management VI1.8 MType not verified+1.8 M
- Price T Rowe Associates1.3 MInvestment firm+1.3 M
- FMR1.2 MInvestment firm+1.2 M
- Shares
- 6.3 M
- Change
- +6.3 M
See more
- Type
- Private equity or venture capital
- Value
- $137M
- Shares
- 6.1 M
- Change
- +6.1 M
See more
- Type
- Private equity or venture capital
- Value
- $133M
- Sofinnova Investmentsconcentrated
- Shares
- 3.6 M
- Change
- +3.6 M
See more
- Type
- Investment firm
- Value
- $77.4M
- Shares
- 2.2 M
- Change
- +2.2 M
See more
- Type
- Bank or trading desk
- Value
- $47.3M
- TRV Gp VI
- Shares
- 2.1 M
- Change
- +2.1 M
See more
- Type
- Single-position portfolio
- Value
- $44.8M
- Shares
- 2.0 M
- Change
- +2.0 M
See more
- Type
- Pension or sovereign fund
- Value
- $42.9M
- Shares
- 1.8 M
- Change
- +1.8 M
See more
- Type
- Bank or trading desk
- Value
- $40.9M
- Foresite Capital Management VI
- Shares
- 1.8 M
- Change
- +1.8 M
See more
- Type
- Type not verified
- Value
- $38.7M
- Shares
- 1.3 M
- Change
- +1.3 M
See more
- Type
- Investment firm
- Value
- $28.4M
- Shares
- 1.2 M
- Change
- +1.2 M
See more
- Type
- Investment firm
- Value
- $25.7M
The 10 13F filers with the most shares as of Jun 30, 2026, whatever their type (index firms usually come first). “Change”: shares added or cut versus the previous quarter, split-adjusted; “no data” = there is no comparable portfolio for the previous quarter (no filing, or a filing with its holdings under confidential treatment). “% of the company” only where shares outstanding are up to date. Entities of the same group file separately and some 13F filings include other managers: there may be double counting. With a free account: the top 25, the largest buyers and the largest sellers.
Held by institutions (13F)
Institutions (13F): 70.0% of the shares · top 10: 52.8% · in index firms: 3.5% of the institutional total
Shares reported by the 54 13F filers as of Jun 30, 2026, divided by the shares outstanding on the cover of the company's latest report (Jun 5, 2026). It is not all institutional ownership: only managers above $100M file a 13F, and it excludes short positions. Entities of the same group file separately and some 13F filings include other managers: there may be double counting. We only publish it where the figure is credible: not for ADRs, companies with more than one share class or stale shares-outstanding data.
Fundamentals
Balance sheet only, for now. SPTX has not yet filed its first annual report (10-K) with the SEC, so there are no 12-month figures (revenue, margins, earnings and cash flow). We show the balance sheet from its latest filing; once the 12-month figures are available, this section fills in automatically.
- Cash and equivalents
- $61.6M
- Investments
- $229M
- Shareholders' equity
- $397M
Balance sheet figures the company filed with the SEC (10-Q or 10-K), in dollars. Net debt = total debt − cash − investments; when negative, the company has more cash than debt (net cash). How each figure is calculated
Insiders (Form 4)
10% owners who bought (6 m): 0
Open-market purchases, excluding 10b5-1 plans. Officers and directors only; joint filers of the same purchase count as one. 10% owners with no role are shown separately. 0 = nobody bought; “no data” = we do not have its Form 4 filings.
Each of the company's Form 4 filings, on EDGAR ↗Latest trades, with date and filing →
Above 5% (13D/13G)
Disclosed stakes, with their amendments. A filing is not always a purchase: there are also reductions and changes of filing entity.
This list may be incomplete: we hold 13D and 13G filings made since Dec 23, 2024. A holder above 5% that has not filed anything since then is not shown here.
Above 5% over time (13D/13G)
Each holder with its filings in order. History since December 2024.
All material events (8-K)
Earnings, agreements, financing, management changes and announcements from the last year, with a filter by type and a link to each filing.
Other Health Care stocks in managers' portfolios
Same sector and a similar number of concentrated managers holding them. It is a list to keep exploring, not a recommendation.
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