Gossamer Bio is trading at $10.10, down -6.31%, with no clear company-specific catalyst identified for the October 6 after-hours decline. - Available search results showed no late-breaking announcement; the latest prominent company news was its September 23 announcement that it submitted a seralutinib NDA. - Major indexes rose during the session. Older concerns about seralutinib’s clinical data and approval uncertainty are noted, but are not established as the cause of this move.