Chen Shu-Chih 4

What Happened Chen Shu‑Chih, a director of Atossa Therapeutics, was granted 10,000 restricted stock units (RSUs) on May 12, 2026. The RSUs were awarded at $0.00 per unit (no immediate cash exchanged). Under the grant each RSU represents a contingent right to one share of common stock; the RSUs vest on the first anniversary of May 12, 2026 (vesting date: May 12, 2027).

Key Details

• Transaction date: 2026-05-12; Filing date (Form 4): 2026-05-14 (filed within the typical 2-business‑day Form 4 window).
• Security: 10,000 RSUs granted; grant price reported as $0.00; total immediate cash value = $0.
• Shares owned after transaction: not specified in the filing.
• Footnotes: F1 — RSUs convert to one share each upon vesting. F2 — Ensisheim Partners, LLC is wholly owned by the reporting person and Dr. Steven C. Quay; the reporting person disclaims beneficial ownership of those Ensisheim-held securities except to the extent of any pecuniary interest.

Context This was a grant/award (code A), not an open‑market purchase or sale. RSU grants create a contingent future ownership interest that only becomes actual stock when the units vest and any applicable withholding is satisfied; they are not an immediate sale or cash transaction. No sale or exercise occurred in this filing.