Altimmune (ALT) CSO vests RSUs, surrenders 4,373 shares for tax

Rhea-AI Filing Summary

Altimmune, Inc. Chief Scientific Officer Roberts M. Scot reported routine equity compensation activity. On January 25, 2026, 14,600 Restricted Stock Units were converted into an equal number of Altimmune common shares at a price of $0 per share, reflecting RSU vesting. On the same date, 4,373 common shares were surrendered to the company at $5.50 per share to cover taxes associated with the RSU vesting, rather than being sold on the open market. After these transactions, Scot directly beneficially owned 84,293 shares of common stock and 29,200 RSUs, which continue to vest in substantially equal annual installments over four years following January 25, 2024, conditioned on continued service.

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

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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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Roberts M Scot

(Last) (First) (Middle)

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)

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

3. Date of Earliest Transaction (Month/Day/Year)
01/25/2026

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
Common Stock, par value $0.0001	01/25/2026		M		14,600	A	$0(1)	88,666	D
Common Stock, par value $0.0001	01/25/2026		F(2)		4,373	D	$5.5	84,293	D

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
Restricted Stock Units	(1)	01/25/2026		M			14,600	(3)	(3)	Common Stock, par value $0.0001	14,600	$0	29,200	D

Explanation of Responses:

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

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

3. The RSUs vest in substantially equal annual installments over the 4 years following January 25, 2024, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date.

	/s/ Gregory Weaver, as Attorney-in-Fact	01/27/2026
	** 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).
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FAQ

What insider transaction did Altimmune (ALT) report for its Chief Scientific Officer?

Altimmune reported that Chief Scientific Officer Roberts M. Scot had 14,600 Restricted Stock Units convert into an equal number of common shares on January 25, 2026, reflecting RSU vesting.

How many Altimmune (ALT) shares were used to cover taxes on the RSU vesting?

A total of 4,373 common shares were surrendered to Altimmune at $5.50 per share in a vesting transaction to cover taxes related to the RSU vesting.

What are Roberts M. Scot’s holdings in Altimmune (ALT) after the reported transactions?

Following the transactions, Roberts M. Scot directly beneficially owned 84,293 shares of Altimmune common stock and 29,200 Restricted Stock Units.

How do the Altimmune (ALT) RSUs held by the CSO vest over time?

The RSUs vest in substantially equal annual installments over four years following January 25, 2024, subject to the CSO’s continued service, and have no expiration date.

Were the Altimmune (ALT) insider transactions open-market sales?

The filing indicates the 4,373 shares were surrendered to the issuer solely to cover taxes from RSU vesting, rather than being sold on the open market.

What does each Altimmune (ALT) RSU reported in this Form 4 represent?

Each Restricted Stock Unit represents a contingent right to receive one share of Altimmune common stock upon vesting.