ALT offering history
Every offering-related filing in Altimmune, Inc.’s recent SEC record — registrations (announced capacity) kept separate from pricing documents (executed sales). Reviewed 1,001 filings back to Dec 15, 2010.
| Date | Filing | What it means | |
|---|---|---|---|
| Apr 24, 2026 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Apr 22, 2026 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Apr 22, 2026 | S-3MEF → | REGISTERED | S-3MEF registration — capacity to sell shares, not a sale yet |
| Jan 28, 2026 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Dec 5, 2025 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Nov 13, 2025 | S-3/A → | REGISTERED | S-3/A registration — capacity to sell shares, not a sale yet |
| Nov 6, 2025 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Nov 6, 2025 | S-3 → | REGISTERED | S-3 registration — capacity to sell shares, not a sale yet |
| Mar 13, 2025 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Feb 27, 2025 | S-3 → | REGISTERED | S-3 registration — capacity to sell shares, not a sale yet |
| Feb 28, 2023 | S-3ASR → | REGISTERED | Automatic shelf registration — effective immediately (large filers) |
| Feb 25, 2021 | 8-K → | EXECUTED | Unregistered share sale disclosed (8-K item 3.02) |
| Feb 25, 2021 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Jan 11, 2021 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Dec 31, 2020 | S-3 → | REGISTERED | S-3 registration — capacity to sell shares, not a sale yet |
| Jul 15, 2020 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Jul 13, 2020 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Jun 1, 2020 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Mar 27, 2020 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Jul 15, 2019 | 8-K → | EXECUTED | Unregistered share sale disclosed (8-K item 3.02) |
| Jul 9, 2019 | 8-K → | EXECUTED | Unregistered share sale disclosed (8-K item 3.02) |
| Apr 12, 2019 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Apr 4, 2019 | S-3 → | REGISTERED | S-3 registration — capacity to sell shares, not a sale yet |
| Mar 11, 2019 | 424B2 → | EXECUTED | Prospectus supplement priced — shares or notes (large filers: often a bond deal) |
| Oct 9, 2018 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Oct 9, 2018 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Oct 1, 2018 | 424B4 → | EXECUTED | Final prospectus — offering priced (typical for IPOs and marketed share deals) |
| Sep 27, 2018 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Sep 26, 2018 | S-1/A → | REGISTERED | S-1/A registration — capacity to sell shares, not a sale yet |
| Sep 24, 2018 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Aug 17, 2018 | S-1/A → | REGISTERED | S-1/A registration — capacity to sell shares, not a sale yet |
| Jul 30, 2018 | S-1 → | REGISTERED | S-1 registration — capacity to sell shares, not a sale yet |
| Jul 16, 2018 | 8-K → | EXECUTED | Unregistered share sale disclosed (8-K item 3.02) |
| Jun 25, 2018 | 8-K → | EXECUTED | Unregistered share sale disclosed (8-K item 3.02) |
| Aug 18, 2017 | 424B5 → | EXECUTED | Shelf takedown priced — shares or notes (small-caps: usually shares; open the filing to confirm) |
| Apr 6, 2017 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Apr 3, 2017 | 424B3 → | UPDATE | Prospectus update — often a resale registration, not necessarily new capital |
| Mar 31, 2017 | EFFECT → | EFFECTIVE | SEC declared a registration effective — selling can begin |
| Mar 30, 2017 | S-3 → | REGISTERED | S-3 registration — capacity to sell shares, not a sale yet |
| Jan 9, 2017 | 424B3 → | UPDATE | Prospectus update — often a resale registration, not necessarily new capital |
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.
ALT offering FAQ
When did ALT last execute an offering?
Per SEC filings, Altimmune, Inc.'s most recent priced offering document is a 424B5 filed 2026-04-24. Note a 424B takedown can price shares or notes (debt) — the linked document says which.
When did ALT last announce or register an offering?
The most recent registration is a S-3MEF filed 2026-04-22. 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.