Offerings // Gossamer Bio, Inc.

GOSS offering history

Every offering-related filing in Gossamer Bio, Inc.’s recent SEC record — registrations (announced capacity) kept separate from pricing documents (executed sales). Reviewed 453 filings back to Jan 19, 2018.

Last executed offering

Jun 5, 2026

8-K — priced deal (shares or notes)

Last registration (announced)

Jan 28, 2026

S-3ASR — capacity, not a sale

Executed, last 12 months

424B pricings + 8-K 3.02 sales

Registered, last 12 months

S-1/S-3/F-series registrations

Date	Filing		What it means
Jun 5, 2026	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Mar 18, 2026	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jan 28, 2026	S-3ASR →	REGISTERED	Automatic shelf registration — effective immediately (large filers)
Sep 25, 2025	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
May 6, 2024	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Aug 28, 2023	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Aug 28, 2023	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Aug 18, 2023	RW →	WITHDRAWN	Registration withdrawn
Aug 18, 2023	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Aug 17, 2023	S-3ASR →	REGISTERED	Automatic shelf registration — effective immediately (large filers)
Jul 20, 2023	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Aug 9, 2022	S-3ASR →	REGISTERED	Automatic shelf registration — effective immediately (large filers)
Jul 13, 2022	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Mar 3, 2022	S-3ASR →	REGISTERED	Automatic shelf registration — effective immediately (large filers)
May 19, 2020	FWP →	MARKETING	Free-writing prospectus — offering being marketed
May 19, 2020	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
May 19, 2020	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
May 18, 2020	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
May 18, 2020	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
May 18, 2020	FWP →	MARKETING	Free-writing prospectus — offering being marketed
Apr 10, 2020	S-3ASR →	REGISTERED	Automatic shelf registration — effective immediately (large filers)
Feb 8, 2019	424B4 →	EXECUTED	Final prospectus — offering priced (typical for IPOs and marketed share deals)
Feb 7, 2019	S-1MEF →	REGISTERED	S-1MEF registration — capacity to sell shares, not a sale yet
Feb 7, 2019	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jan 30, 2019	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Jan 30, 2019	FWP →	MARKETING	Free-writing prospectus — offering being marketed
Jan 24, 2019	FWP →	MARKETING	Free-writing prospectus — offering being marketed
Jan 23, 2019	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Dec 21, 2018	S-1 →	REGISTERED	S-1 registration — capacity to sell shares, not a sale yet

GOSS offering-related filings from SEC EDGAR, newest first (capped at 40). Each links to the original document.

Two honest limits. (1) A 424B takedown can price shares or notes— EDGAR’s metadata doesn’t say which, so open the document: large investment-grade filers use these mostly for bond deals (no dilution), small-caps mostly for shares. (2) At-the-market (ATM) programs sell shares gradually and individual sales are not separately filed — the visible footprint is the enabling shelf and its 424B5; actual ATM share counts surface later in the 10-Q/10-K share count. Educational information from public filings, not investment advice.

Is a shelf active now? →Do they need money? →Red flags →Full GOSS workspace →

GOSS offering FAQ

When did GOSS last execute an offering?

Per SEC filings, Gossamer Bio, Inc.'s most recent priced offering document is a 8-K filed 2026-06-05. Note a 424B takedown can price shares or notes (debt) — the linked document says which.

When did GOSS last announce or register an offering?

The most recent registration is a S-3ASR filed 2026-01-28. A registration is capacity to sell shares — not a sale.

Does an offering always mean dilution?

Registered direct offerings and shelf takedowns issue new shares and dilute existing holders. Resale registrations (424B3/B7) let existing holders sell and do not create new shares. Secondary sales by insiders also do not dilute. Each row here is labeled with what it is.