[Form 4] Altimmune, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Altimmune director Mitchel Sayare was granted an option to purchase 48,800 shares of common stock at a $3.92 exercise price. The option was granted on 09/25/2025, becomes exercisable in substantially equal monthly installments over the 12 months following that date, and expires on 09/25/2035. The reporting on Form 4 indicates the position is held directly. The filing is signed by an attorney-in-fact on behalf of the reporting person.

Positive

• Director equity grant aligns the reporting person's incentives with shareholders by providing ownership upside
• Clear vesting schedule (monthly over 12 months) conditions attainment on continued service

Negative

• Potential dilution from issuance of 48,800 shares underlying the option if exercised
• No information provided on relative size of the grant versus outstanding shares to assess materiality

Insights

Securities Analyst

TL;DR: Director received a time‑vesting stock option for 48,800 shares at $3.92, standard for incentive alignment.

The grant on 09/25/2025 awards an option exercisable over 12 months with a ten‑year term to 09/25/2035. This is a routine director equity grant intended to align interests with shareholders. The direct ownership form is documented and the filing was executed by an attorney‑in‑fact. The disclosure contains clear vesting schedule language and no other compensation or cash transactions.

Corporate Governance Expert

TL;DR: Governance signal is neutral; equity grant vests monthly over one year, showing short‑term service requirement.

The option vests in substantially equal monthly installments during the 12 months after 09/25/2025, implying the reporting person must remain in service to realize full benefit. The Form 4 shows direct beneficial ownership post‑grant. There are no additional governance events, departures, or related party disclosures in this filing.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

SAYARE MITCHEL

(Last) (First) (Middle)

C/O ALTIMMUNE, INC., 910 CLOPPER ROAD,

SUITE 201S

(Street)

GAITHERSBURG MD 20878

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Altimmune, Inc. [ ALT ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/25/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (option to buy)	$3.92	09/25/2025		A		48,800		(1)	09/25/2035	Common Stock, par value $0.0001	48,800	$0.00	48,800	D

Explanation of Responses:

1. The shares underlying the option become vested and exercisable in substantially equal monthly installments over the 12 months following September 25, 2025, subject to the reporting person's continued service through the applicable vesting date.

Remarks:

Exhibit 24 - Power of Attorney

	/s/ Gregory Weaver, as Attorney-in-Fact	09/29/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Altimmune insider Mitchel Sayare receive on 09/25/2025?

He was granted a stock option to buy 48,800 shares of common stock at an exercise price of $3.92 per share.

When do the options granted to Mitchel Sayare become exercisable and when do they expire?

The options vest in substantially equal monthly installments over the 12 months following 09/25/2025 and expire on 09/25/2035.

Is the reported ownership direct or indirect for the Form 4 filing?

The filing reports direct (D) ownership of the 48,800 underlying shares following the reported transaction.

Who signed the Form 4 filing for Mitchel Sayare?

The Form 4 signature block shows the filing was signed by Gregory Weaver, as Attorney‑in‑Fact on 09/29/2025.

Does the Form 4 disclose any cash payments or sales related to this transaction?

No. The filing shows an option grant (derivative) with an exercise price of $3.92 and no cash sale or disposal reported.