Offerings // ATOSSA THERAPEUTICS, INC.

ATOS offering history

Every offering-related filing in ATOSSA THERAPEUTICS, INC.’s recent SEC record — registrations (announced capacity) kept separate from pricing documents (executed sales). Reviewed 638 filings back to Mar 30, 2010.

Last executed offering

Jun 12, 2026

424B5 — priced deal (shares or notes)

Last registration (announced)

May 13, 2024

S-3 — 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 12, 2026	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
Feb 20, 2026	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Feb 20, 2026	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
Nov 19, 2024	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
May 23, 2024	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
May 13, 2024	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Apr 29, 2021	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Apr 21, 2021	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Mar 23, 2021	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
Mar 22, 2021	S-3MEF →	REGISTERED	S-3MEF registration — capacity to sell shares, not a sale yet
Feb 4, 2021	424B2 →	EXECUTED	Prospectus supplement priced — shares or notes (large filers: often a bond deal)
Jan 29, 2021	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jan 22, 2021	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Jan 8, 2021	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Dec 21, 2020	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
Dec 11, 2020	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Dec 8, 2020	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Dec 1, 2020	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Nov 20, 2020	S-1 →	REGISTERED	S-1 registration — capacity to sell shares, not a sale yet
Sep 25, 2020	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Sep 10, 2020	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Sep 2, 2020	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Feb 7, 2020	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Jun 14, 2018	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Jun 4, 2018	S-1 →	REGISTERED	S-1 registration — capacity to sell shares, not a sale yet
May 16, 2018	FWP →	MARKETING	Free-writing prospectus — offering being marketed
May 10, 2018	424B4 →	EXECUTED	Final prospectus — offering priced (typical for IPOs and marketed share deals)
May 9, 2018	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
May 3, 2018	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Apr 23, 2018	S-1/A →	REGISTERED	S-1/A registration — capacity to sell shares, not a sale yet
Mar 27, 2018	S-1 →	REGISTERED	S-1 registration — capacity to sell shares, not a sale yet
Dec 22, 2017	8-K →	EXECUTED	Unregistered share sale disclosed (8-K item 3.02)
Dec 21, 2017	424B5 →	EXECUTED	Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm)
Oct 27, 2017	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Oct 26, 2017	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Oct 5, 2017	EFFECT →	EFFECTIVE	SEC declared a registration effective — selling can begin
Sep 22, 2017	S-3 →	REGISTERED	S-3 registration — capacity to sell shares, not a sale yet
Jul 3, 2017	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Mar 31, 2017	424B3 →	UPDATE	Prospectus update — often a resale registration, not necessarily new capital
Mar 30, 2017	FWP →	MARKETING	Free-writing prospectus — offering being marketed

ATOS 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 ATOS workspace →

ATOS offering FAQ

When did ATOS last execute an offering?

Per SEC filings, ATOSSA THERAPEUTICS, INC.'s most recent priced offering document is a 424B5 filed 2026-06-12. Note a 424B takedown can price shares or notes (debt) — the linked document says which.

When did ATOS last announce or register an offering?

The most recent registration is a S-3 filed 2024-05-13. 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.