Atossa Therapeutics, Inc.'s SEC filings document a clinical-stage biopharmaceutical issuer focused on (Z)-endoxifen development in oncology and rare disease settings. Its reports include financial-result 8-Ks, corporate updates, Regulation FD communications, and disclosures tied to research and development spending for its lead product candidate.
The filing record also covers governance and capital-structure matters, including annual meeting votes, director elections, auditor ratification, executive-compensation votes, charter-authority proposals, Form S-3 and at-the-market offering disclosures, Nasdaq listing compliance, and material events involving Endoxifen-related intellectual property proceedings and settlement agreements.
Atossa Therapeutics, Inc. is implementing a 1-for-15 reverse stock split of its common stock, effective at 12:01 a.m. Eastern Time on February 2, 2026. At that time, each 15 shares of common stock will automatically be combined into one share, and the stock is expected to begin trading on a split-adjusted basis the same day under a new CUSIP, while keeping the ATOS ticker and the $0.18 par value per share.
No fractional shares will be issued; instead, stockholders will receive cash equal to the fractional share multiplied by the closing price of the stock on January 30, 2026, adjusted for the split. The company will make proportional adjustments to outstanding equity awards, plan share reserves, and the conversion terms of its Series B Convertible Preferred Stock. The reverse split was enabled by stockholder approval of an amendment allowing a reverse split in a range of 5:1 to 20:1, with 33,724,885 votes for, 27,888,393 against and 130,938 abstentions, out of 129,171,424 shares entitled to vote as of December 19, 2025.
Atossa Therapeutics President & CEO Steven C. Quay, who also serves as a director, reported new equity awards dated January 20, 2026. He received 325,203 restricted stock units (RSUs), each representing one share of common stock, which will vest one year from the grant date. He was also granted 950,000 stock options with an exercise price of $0.603, vesting quarterly over 24 months following January 20, 2026, contingent on continued service.
Following these awards, Quay directly beneficially owns 339,101 shares of common stock and indirectly holds 22,254 shares through Ensisheim Partners, LLC, an entity he co‑owns with Dr. Shu‑Chih Chen, with shared voting and investment power and a disclaimer of beneficial ownership beyond his pecuniary interest.
Atossa Therapeutics, Inc. released an updated corporate presentation that includes a preliminary estimate of its cash and cash equivalents. The company estimates it held approximately $40 million in cash and cash equivalents as of December 31, 2025.
This cash figure is unaudited, based on internal closing procedures for the fourth quarter and full year 2025, and may change once final results are completed. Atossa stresses that this estimate alone does not provide a full picture of its financial condition or results of operations and cautions investors not to place undue reliance on it.
The presentation also discusses forward-looking expectations for the development and potential regulatory path of the company’s lead program, (Z)-Endoxifen, including possible indications, approval prospects and market opportunities, all of which are subject to significant clinical, regulatory, financing and Nasdaq listing-compliance risks.
Atossa Therapeutics, Inc. reported that on January 6, 2026 the U.S. Food and Drug Administration issued a “Study May Proceed” letter for the company’s study of metastatic breast cancer. This type of letter indicates the FDA has reviewed the planned clinical study and is allowing it to go forward under its current design.
The company disclosed this development through a press release, which is attached as an exhibit to the report. The update highlights progress in Atossa’s efforts to clinically evaluate its approach in patients with metastatic breast cancer, an advanced stage of the disease where new treatment options are often needed.
Atossa Therapeutics (ATOS) reported Q3 2025 results showing a net loss of $8.7M (loss per share $0.07) as the company advanced its (Z)-endoxifen programs. Operating expenses were $9.3M, driven by R&D of $5.4M (up 57% year over year) and G&A of $3.9M (up 31%). Interest income was $0.6M.
For the nine months, net loss was $23.8M and cash used in operations was $19.2M. Cash and cash equivalents totaled $51.8M with working capital of $47.5M, and management believes cash funds operations for at least one year. The company maintains an at-the-market facility of up to $100.0M with no sales during 2025 to date. Following warrant expirations, no warrants were outstanding at September 30, 2025.
As of November 1, 2025, shares outstanding were 129,171,424; this is a baseline figure, not the amount being offered. ATOS received PTAB institution decisions on two patent challenges, with responses due by January 26, 2026. Nasdaq is monitoring minimum bid price compliance after an additional review period.
Atossa Therapeutics, Inc. filed a current report to furnish a press release announcing its financial results for the quarter ended September 30, 2025 and providing a company update. The press release, dated November 12, 2025, is included as Exhibit 99.1 and incorporated by reference into this report. The company clarifies that the information in Items 2.02 and 9.01, including Exhibit 99.1, is being furnished rather than filed under securities law, which limits its use for certain liability provisions.
Atossa Therapeutics (ATOS) reported an insider equity award on Form 4. The company’s Chief Financial Officer received a stock option grant to purchase 578,000 shares at an exercise price of $1.03 per share, with a transaction date of October 14, 2025.
The options vest as follows: 25% on October 14, 2026, with the remaining 75% vesting in equal quarterly installments over the following three years, subject to continued service. The options expire on October 14, 2035. Ownership is listed as Direct.
Atossa Therapeutics (ATOS) filed a Form 3 initial statement of beneficial ownership for its Chief Financial Officer, Mark James Daniel, with a date of event of 10/14/2025. The filing states that no securities are beneficially owned. The submission includes an Exhibit 24 Power of Attorney and is filed by one reporting person.
Atossa Therapeutics (ATOS) appointed Mark Daniel as Chief Financial Officer and principal accounting officer, effective October 14, 2025, succeeding Heather Rees. Ms. Rees will remain as a non-officer employee through November 15, 2025 to assist the transition and will receive nine months of base salary and nine months of employer-paid COBRA under a separation agreement.
Mr. Daniel’s employment agreement includes a base salary of $415,900 and a target annual bonus of up to 40% of base salary beginning in fiscal 2026. He will receive an option to purchase 578,000 shares with an exercise price set at the grant-date close, vesting 25% on the first anniversary and the remainder in equal quarterly installments over three years. If terminated without Cause or for Good Reason (outside a change in control window), he is eligible for six months’ salary (50% of base) and up to six months of COBRA. Upon qualifying termination in connection with a change in control, benefits include a lump sum equal to 1.0x base salary plus target bonus, pro rata bonus, full equity acceleration, and up to twelve months of COBRA.
Atossa Therapeutics, Inc. reported that it has made an updated corporate presentation available as of September 26, 2025. The presentation is furnished as an exhibit to this report under a Regulation FD disclosure item, meaning it is intended to share information broadly with the market.
The company notes that this material is being furnished, not filed, so it is not subject to certain liability provisions of the federal securities laws and is not automatically incorporated into other SEC filings. The exhibit is identified as a corporate presentation dated September 26, 2025.