General Atlantic, L.P. disclosed an 11.5% stake in Seaport Therapeutics, Inc. common stock. The group filed a Schedule 13D on May 11, 2026, after Seaport’s May 4 IPO converted its preferred shares and the fund bought additional shares at $18.00 in the offering. The shift from a prior 13G eligibility to a 13D signals room for more active engagement.

Investor Intent

General Atlantic says it holds the shares for investment and plans to engage with other shareholders, company leaders, and directors. The firm may "make suggestions concerning the Company's operations" and board composition, and it could buy more shares or sell shares over time based on how the business performs.

A lock-up limits sales and hedging for 180 days after May 1, 2026, with transfers only to affiliates that honor the same terms. Beyond the lock-up, General Atlantic "may, from time to time, make additional purchases" or reduce its position, and it may use derivatives with institutional counterparties tied to Seaport’s stock.

Investor's Background

General Atlantic, L.P. is a Delaware limited partnership that invests in companies for long-term growth. The firm is a global growth equity investor known for backing healthcare, technology, and life sciences businesses. It typically partners with management teams, provides strategic guidance, and supports scaling and governance.

Original SEC Filing: Seaport Therapeutics, Inc. [ SPTX ] - SCHEDULE 13D - May. 11, 2026