Seaport Therapeutics joined Nasdaq on May 1 after its parent, Puretech Health, moved to exit the U.S. market in favor of a sole listing on the London Stock Exchange. Seaport raised gross proceeds of $254.9 million, continuing a broader wave of large biotech IPOs. The structure follows Puretech’s effort to reduce costs and administrative overhead, while Seaport—ticker SPTX—remains tied to Puretech through a stated 35.1% ownership stake. The deal also reflects Puretech’s plan to spin out clinical assets into independent companies funded earlier in development. For CNS-focused development, the immediate priority is funding and clinical execution following the public listing. The Nasdaq move may also change visibility for stakeholders watching Seaport’s transition from a private-stage build to a capital-markets cadence.