Shu-Chih Chen - 12 May 2026 Form 4 Insider Report for ATOSSA THERAPEUTICS, INC. (ATOS)

Reporting relationship: Director
Issuer ticker: ATOS
Reported as of: 12 May 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 14 May 2026, 16:27:40 UTC
Prior SEC filing: 16 May 2025
Source filing: View source filing
Reporting owner signature: Shu-Chih Chen

Key filing fact

Shu-Chih Chen filed Form 4 for ATOSSA THERAPEUTICS, INC. (ATOS) on 14 May 2026.

Key facts

This page summarizes Shu-Chih Chen's Form 4 filing for ATOSSA THERAPEUTICS, INC. (ATOS).
1 reported transaction and 0 derivative rows are listed below.
Accepted by SEC: 14 May 2026, 16:27.

Change

Previous filing in this sequence was filed on 16 May 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0001552127 Primary reporting owner

Chen Shu-Chih

Relationship: Director
Address: C/O ATOSSA THERAPEUTICS, INC., 1448 NW MARKET STREET SUITE 500, SEATTLE
Signature: Shu-Chih Chen
Signature date: 14 May 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

ATOS transaction

Common Stock

Award

Transaction value
Shares: +10,000
Change %
Price: $0.000000^*
Shares after: 10,000
Date: 12 May 2026
Ownership: Direct
Footnotes: F1

ATOS holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after: 1,483
Date: 12 May 2026
Ownership: By Ensisheim Partners, LLC
Footnotes: F2

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

Represents a grant of restricted stock units ("RSUs"). Each RSU represents a contingent right to receive one share of the Issuer's Common Stock. The RSUs shall vest on the first anniversary of May 12, 2026.

Footnote F2

Ensisheim Partners, LLC ("Ensisheim") is wholly owned by the Reporting Person and Dr. Steven C. Quay. The Reporting Person and Dr. Quay share voting and investment power over the securities held by Ensisheim. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.