Seaport Therapeutics, Inc. SEC Filings

Seaport Therapeutics, Inc. reports that Steven M. Paul beneficially owns 3,516,718 shares of its Voting Common Stock as of June 30, 2026. This amount represents 6.3% of the 53,530,550 shares of Common Stock stated to be outstanding on that date.

The position consists of 863,031 shares held of record by Steven M. Paul and 2,653,687 shares underlying stock options that are exercisable within 60 days of June 30, 2026. He has sole voting and dispositive power over all 3,516,718 shares and no shared voting or dispositive power.

Seaport Therapeutics, a clinical-stage neuropsychiatry company using its proprietary Glyph platform, reported a net loss of $62.6 million for Q2 2026 and $88.0 million for the first half of 2026. Year-to-date operating expenses were $93.4 million, including $46.0 million in research and development and $47.3 million in general and administrative costs. G&A expenses reflect substantial non-cash stock-based compensation, including $37.6 million in general and administrative awards and $1.8 million in research and development.

Liquidity improved following the IPO. As of June 30, 2026, total assets were $441.7 million, including $427.3 million of cash, cash equivalents and U.S. Treasury investments, which management believes will fund operations for at least twelve months. During Q2 2026, the company completed its IPO, issuing 14,446,658 shares at $18.00 per share for approximately $238.4 million in net proceeds, and all preferred stock converted into common shares, resulting in 53,530,550 common shares outstanding.

Pipeline programs advanced. Lead candidate GlyphAllo is in the Phase 2b BUOY-1 trial in major depressive disorder, with topline data expected in the first half of 2027, and a Phase 1 driving simulation study reading out in the second half of 2026. GlyphAgo completed Phase 1 with favorable pharmacokinetics and safety, with Phase 2 trials in generalized anxiety disorder planned from late 2026.

Seaport Therapeutics reported second-quarter 2026 results and detailed progress across its neuropsychiatry pipeline. Enrollment in the Phase 2b BUOY-1 trial of GlyphAllo in major depressive disorder is on track, with topline data expected in the first half of 2027, and a Phase 1 driving-simulation trial is expected to read out in the second half of 2026.

The company reported positive Phase 1 proof-of-concept data for GlyphAgo in generalized anxiety disorder, including a 6.8-fold increase in bioavailability and 10-fold lower pharmacokinetic variability versus unmodified agomelatine, supporting planned Phase 2a and 2b trials starting in 2026 and 2027. Preclinical candidate Glyph2BLSD is expected to complete first-in-human-enabling studies by year-end 2027.

In May 2026 Seaport completed an upsized IPO raising $260.0 million in gross proceeds, ending June 30, 2026 with $427.3 million in cash, cash equivalents, and investments, which it expects to fund operations into 2029. Higher R&D and one-time, non-cash stock-based compensation drove a wider net loss of $62.6 million for the quarter, compared with $15.1 million a year earlier.

Seaport Therapeutics director–related trust bought additional stock. On behalf of the Robert Joseph Hombach Revocable Trust, an open-market purchase of 13,000 shares of Seaport Therapeutics common stock was made at a weighted average price of $18.136 per share, with individual trades ranging from $17.65 to $18.27.

After this transaction, the trust holds 13,000 shares indirectly attributed to director Robert J. Hombach. He disclaims beneficial ownership of these shares for Section 16 purposes except to the extent of any pecuniary interest.

Seaport Therapeutics, Inc. is a clinical‑stage biotech developing oral therapies for depression, anxiety and other neuropsychiatric disorders using its Glyph platform. For the quarter ended March 31, 2026, it reported a net loss of $25.4 million, wider than $13.1 million a year earlier, driven mainly by higher research and development spending.

R&D expenses nearly doubled to $21.4 million as the company advanced its lead candidate GlyphAllo into a Phase 2b BUOY‑1 trial in major depressive disorder and ran supporting studies, while GlyphAgo progressed through Phase 1 with favorable bioavailability and safety data. General and administrative expenses were $6.1 million, reflecting public‑company preparation and growth in corporate infrastructure.

Seaport ended the quarter with $52.9 million in cash and cash equivalents and $159.7 million in U.S. Treasury investments, totaling $212.6 million in cash and investments. Management states that, combined with approximately $238.7 million of net proceeds from its second‑quarter 2026 IPO, these resources are expected to fund operations into 2029 while the pipeline advances through multiple planned Phase 2 trials.

Seaport Therapeutics reported a larger first-quarter 2026 loss while significantly strengthening its balance sheet and advancing its neuropsychiatry pipeline. Net loss was $25.4M, compared with $13.1M a year earlier, driven mainly by higher research and development spending of $21.4M as lead programs moved into later-stage trials.

Cash, cash equivalents, and investments totaled $212.6M as of March 31, 2026. In May, Seaport completed an upsized IPO generating gross proceeds of $260.0M, and now expects its current cash to fund operations into 2029. The company highlighted progress across its GlyphAllo and GlyphAgo programs, including a potentially registration-enabling Phase 2b MDD trial, new Phase 1 data supporting dose selection in GAD, and plans for multiple Phase 2 studies with topline readouts extending through 2028.

General Atlantic and affiliated funds filed a Schedule 13D disclosing beneficial ownership of 6,101,582 shares of Seaport Therapeutics common stock, representing 11.5% of the company. This stake reflects both pre‑IPO preferred holdings and new IPO purchases.

At the IPO closing, 10,526,315 shares of Series B convertible preferred stock held by General Atlantic (SP), L.P. automatically converted into 3,351,582 common shares, and GA SP purchased an additional 2,750,000 common shares at $18.00 per share. Multiple General Atlantic entities are treated as a coordinated “group” with shared voting and dispositive power over the position.

The filing states the investment is for general investment purposes but notes the group may engage with management and other shareholders and could increase, reduce, or hedge its position over time. GA SP is also party to a customary 180‑day IPO lock‑up, limiting sales and certain hedging transactions through late October 2026.

Seaport Therapeutics ownership filing: The Goldman Sachs Group, Inc. and Goldman Sachs & Co. LLC report beneficial ownership of 2,791,814 shares of Seaport Therapeutics Voting Common Stock, representing 5.5% of the class. The filing is a joint Schedule 13G filed in early May 2026 and identifies shared voting and dispositive power of 2,791,814 shares held by the reporting entities.

Seaport Therapeutics, Inc. filed an initial Form 3 showing that General Atlantic–affiliated funds hold 6,101,582 shares of its Common Stock. This amount includes 3,351,582 shares issuable upon conversion of Series B preferred stock. The holdings are reported as indirect, through multiple partnerships and investment vehicles described in the footnotes. A six-member Partnership Committee ultimately controls key general partners, and each member disclaims beneficial ownership of the shares except to the extent of any pecuniary interest.