Seaport Therapeutics Prices $254.9M IPO at $18 Share, Sets Nasdaq Debut

Seaport Therapeutics priced its IPO at $18 per share for 14.16 million shares, raising $254.9 million in gross proceeds and preparing to trade on Nasdaq under ticker SPTX starting May 1, 2026.

Seaport Therapeutics is a neuropsychiatry company founded by PureTech Health. The IPO price sits at the top of the indicated range, reflecting strong investor interest. PureTech will continue to hold a sizable stake after the offering.

The offering consists of 14,160,000 shares at $18.00 each, yielding $254.9 million before fees. Underwriters hold a 30‑day option to buy up to 2,124,000 additional shares at the same price. After the IPO closes, PureTech expects to retain 16,685,013 shares of Seaport. Assuming the greenshoe is fully exercised, total proceeds could reach approximately $293.1 million. Post‑offering, the combined share count (including PureTech’s stake) would be about 30.85 million, implying a market cap near $555 million at the IPO price.

The capital will fund Seaport’s pipeline of neuropsychiatry therapies and general corporate needs. PureTech’s retained ownership aligns its financial upside with Seaport’s performance. Investors should watch the Nasdaq debut on May 1, 2026, and any decision by underwriters to exercise the greenshoe option, which would increase the free float and potentially affect early‑trading dynamics.