Linda M. Richardson - 16 Sep 2026 Form 4 Insider Report for Altimmune, Inc. (ALT)

Reporting relationship: Chief Commercial Officer
Issuer ticker: ALT
Reported as of: 16 Sep 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 17 Sep 2026, 16:05:29 UTC
Prior SEC filing: 17 Sep 2025
Source filing: View source filing
Reporting owner signature: /s/ Gregory Weaver, as Attorney-in-Fact

Key filing fact

Linda M. Richardson filed Form 4 for Altimmune, Inc. (ALT) on 17 Sep 2026.

Key facts

This page summarizes Linda M. Richardson's Form 4 filing for Altimmune, Inc. (ALT).
3 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 17 Sep 2026, 16:05.

Change

Previous filing in this sequence was filed on 17 Sep 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 0001595064 Primary reporting owner

Richardson Linda M

Relationship: Chief Commercial Officer
Address: 910 CLOPPER ROAD, SUITE 201S, GAITHERSBURG
Signature: /s/ Gregory Weaver, as Attorney-in-Fact
Signature date: 17 Sep 2026

Reported non-derivative transactions

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

ALT transaction

Common Stock, par value $0.0001

Options Exercise

Transaction value
Shares: +24,000
Change %
Price: $0.000000^*
Shares after: 24,000
Date: 16 Sep 2026
Ownership: Direct
Footnotes: F1

ALT transaction

Common Stock, par value $0.0001

Tax liability

Transaction value
Shares: -6,826
Change %: -28%
Price: $3.24^*
Shares after: 17,174
Date: 16 Sep 2026
Ownership: Direct
Footnotes: F2

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

ALT transaction Derivative

Restricted Stock Units

Options Exercise

Transaction value
Shares: -24,000
Change %: -25%
Price: $0.000000^*
Shares after: 72,000
Date: 16 Sep 2026
Ownership: Direct
Underlying class: Common Stock, par value $0.0001
Underlying amount: 24,000
Exercise price
Footnotes: F1, F3

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

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 3 footnotes

Footnote F1

Each Restricted Stock Unit ("RSU") represents a contingent right to receive one share of Common Stock, par value $0.0001, when vested.

Footnote F2

Vesting transaction: Shares surrendered to the Issuer solely to cover taxes associated with vesting of RSUs.

Footnote F3

The RSUs become vested over four (4) years with 25% of the shares vesting on September 16, 2026, with the remainder vesting in equal annual installments for the following three (3) years, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date.