Latest Period
Q2 2026
Security Snapshot
Seaport Therapeutics, Inc. - Voting Common Stock, $0.001 par value per share (SPTX) Institutional Ownership
CUSIP: 81221K108
13F Institutional Holders and Ownership History for Q2 2026
Institutions Reporting
54
Shares (Excl. Options)
37,408,896
Price
$21.72
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- Security type / class
- Equity / Voting Common Stock, $0.001 par value per share
- Symbol
- SPTX on Nasdaq
- All holders as of 30 Jun 2026
- Q2 2026
- Total 13F shares
- 37,408,896
- Total 13F value
- $813,850,806
- Portfolio coverage rank
- 0.01%
- Share change
- +37,408,896
- Value change
- +$813,850,806
- Number of holders
- 54
- Shares outstanding
- 53,477,606
- SEC-reported price per share
- $23.80
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
2 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- SPTX - Seaport Therapeutics, Inc. - Voting Common Stock, $0.001 par value per share is tracked under CUSIP 81221K108.
- 54 institutions reported positions in Q2 2026.
- 3 significant owners is listed from Schedule 13D/13G reporting.
Change
- Latest quarter on this page is Q2 2026.
- Additional quarter-over-quarter change detail appears as history expands.
Research use
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 54 institutions filings for Q2 2026.
Security key
81221K108
Latest holder period
Q2 2026
13F holders
54
13D/G owners
3
CIK / CUSIP context first
Open Q2 2026 holders
SPTX full holder history
Seaport Therapeutics, Inc. SEC filings
Seaport Therapeutics, Inc. company facts
Seaport Therapeutics, Inc. insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 81221K108:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
3
Security
SPTX
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| PureTech LYT, Inc. | 31% | $335,368,761 | 16,685,013 | PureTech Health plc | 30 Jun 2026 | |||
| Zohar Daphne | 9.1% | $105,032,490 | 5,225,497 | Zohar Daphne | 30 Jun 2026 | |||
| PAUL STEVEN M | 6.3% | $70,686,032 | 3,516,718 | PAUL STEVEN M | 30 Jun 2026 |
As of 30 Jun 2026, 54 institutional investors reported holding 37,408,896 shares of Seaport Therapeutics, Inc. - Voting Common Stock, $0.001 par value per share (SPTX). This represents 70% of the company’s total 53,477,606 outstanding shares.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
68%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| ARCH Venture Management, LLC | 12% | 6,294,951 | 12% | $136,600,437 | |
| GENERAL ATLANTIC, L.P. | 11% | 6,101,582 | 4.6% | $132,526,361 | |
| Sofinnova Investments, Inc. | 6.7% | 3,564,871 | 4.1% | $77,428,998 | |
| GOLDMAN SACHS GROUP INC | 4.1% | 2,178,642 | 0% | $47,320,104 | |
| TRV GP VI, LLC | 3.9% | 2,061,222 | 19% | $44,769,742 | |
| CANADA PENSION PLAN INVESTMENT BOARD | 3.7% | 1,975,791 | 0.02% | $42,914,181 | |
| JPMORGAN CHASE & CO | 3.4% | 1,815,845 | 0% | $40,892,829 | |
| Foresite Capital Management VI LLC | 3.3% | 1,779,521 | 6% | $38,651,196 | |
| PRICE T ROWE ASSOCIATES INC /MD/ | 2.4% | 1,308,604 | 0% | $28,424,000 | |
| FMR LLC | 2.2% | 1,185,100 | 0% | $25,740,372 | |
| Bellevue Group AG | 2.1% | 1,100,000 | 0.5% | $23,892,000 | |
| Siren, L.L.C. | 2% | 1,095,316 | 0.48% | $23,790,264 | |
| JENNISON ASSOCIATES LLC | 2% | 1,079,669 | 0.01% | $23,450,411 | |
| RA CAPITAL MANAGEMENT, L.P. | 1.3% | 700,000 | 0.13% | $15,204,000 | |
| VANGUARD CAPITAL MANAGEMENT LLC | 1.1% | 599,217 | 0% | $13,014,993 | |
| Woodline Partners LP | 1.1% | 586,345 | 0.04% | $12,735,413 | |
| PERCEPTIVE ADVISORS LLC | 0.93% | 500,000 | 0.17% | $10,860,000 | |
| BRAIDWELL LP | 0.93% | 500,000 | 0.4% | $10,860,000 | |
| PRINCIPAL FINANCIAL GROUP INC | 0.78% | 414,672 | 0% | $9,006,677 | |
| Aberdeen Group plc | 0.58% | 310,355 | 0.01% | $6,740,911 | |
| UBS Group AG | 0.52% | 279,184 | 0% | $6,063,876 | |
| BlackRock, Inc. | 0.43% | 229,863 | 0% | $4,992,624 | |
| SEVEN GRAND MANAGERS, LLC | 0.42% | 225,000 | 0.2% | $4,887,000 | |
| CITADEL ADVISORS LLC | 0.36% | 191,144 | 0% | $4,151,648 | |
| GEODE CAPITAL MANAGEMENT, LLC | 0.33% | 175,866 | 0% | $3,821,843 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
1
Latest
Q2 2026
Rows shown
1-1 of 1
| Period | 13F Shares, Excl. Options | Value, Excl. Options | Value Change | Price (Median) | Investors |
|---|---|---|---|---|---|
| 2026 Q2 | 37,408,896 | $813,850,806 | +$813,850,806 | $21.72 | 54 |