[Form 4] Altimmune, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Altimmune, Inc. (ALT) director Jerome Benedict Durso was granted stock options on 09/25/2025 to purchase 48,800 shares of common stock at an exercise price of $3.92 per share. The options become exercisable in substantially equal monthly installments over the 12 months following the grant date, subject to continued service. Following the grant, Durso beneficially owns 48,800 options. The Form 4 was filed by a single reporting person and signed by an attorney-in-fact on 09/29/2025.

Positive

• Director grant aligns incentives: Options vest over 12 months tying compensation to continued service
• Clear terms disclosed: Grant date, exercise price ($3.92), quantity (48,800) and vesting schedule are explicitly stated

Negative

• None.

Insights

Financial Analyst

TL;DR: A director received a standard service-vesting option grant of 48,800 shares at $3.92, a routine executive compensation event.

The grant of 48,800 options at a $3.92 exercise price appears to be a typical equity-based retention or compensation award for a director. Vesting monthly over 12 months ties exercise to continued service rather than immediate liquidity, which is common for alignment with shareholder interests. The disclosure shows direct ownership of the options and no immediate cash proceeds or exercises, indicating no change in outstanding common shares until options are exercised.

Corporate Governance Expert

TL;DR: This Form 4 documents a time-based director option grant with standard vesting—material for insider holdings but not an operational disclosure.

The filing documents that Jerome Benedict Durso, a director, received options exercisable for 48,800 shares, vested monthly over one year. From a governance perspective, time-based vesting promotes continued board service. The Form 4 provides clear terms: grant date, exercise price, vesting schedule, and post-grant beneficial ownership. There is no indication of accelerated vesting, related-party transactions beyond standard director compensation, or changes to exercised shares 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
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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^*

Durso Jerome Benedict

(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.

	/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 transaction did Jerome Benedict Durso report on the Form 4 for ALT?

He reported receipt of stock options to purchase 48,800 shares on 09/25/2025 at an exercise price of $3.92 per share.

When do the options granted to the ALT director become exercisable?

The options become exercisable in substantially equal monthly installments over the 12 months following September 25, 2025, subject to continued service.

How many options does the reporting person beneficially own after the reported transaction?

Following the reported transaction, the reporting person beneficially owns 48,800 options.

Was the Form 4 filed by more than one reporting person?

No. The form indicates it was filed by one reporting person and was signed by an attorney-in-fact on 09/29/2025.

What is the exercise price and expiration information disclosed for the options?

The exercise price is $3.92. The option listing includes an expiration date of 09/25/2035 and shows 48,800 underlying shares.