Altimmune (ALT) CSO logs RSU vesting, tax surrenders, ESPP buy

Rhea-AI Filing Summary

Altimmune Chief Scientific Officer Scot M. Roberts reported multiple equity transactions involving company stock. On January 30, 2026, 9,275 restricted stock units (RSUs) vested and were settled into common shares, with 2,859 shares surrendered to Altimmune to cover taxes. On January 31, 2026, he acquired 5,567 shares through the 2019 Employee Stock Purchase Plan at $3.07 per share, based on 85% of the August 1, 2025 closing price. On February 2, 2026, a further 7,775 RSUs vested into common stock and 2,329 shares were surrendered for taxes. After these transactions, he directly held 112,824 shares of Altimmune common stock.

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)
01/30/2026

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	01/30/2026		M		9,275	A	$0(1)	104,670	D
Common Stock, par value $0.0001	01/30/2026		F(2)		2,859	D	$5.6	101,811	D
Common Stock, par value $0.0001	01/31/2026		A(3)		5,567	A	$3.07(4)	107,378	D
Common Stock, par value $0.0001	02/02/2026		M		7,775	A	$0(1)	115,153	D
Common Stock, par value $0.0001	02/02/2026		F(2)		2,329	D	$5.55	112,824	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)	01/30/2026		M			9,275	(5)	(5)	Common Stock, par value $0.0001	9,275	$0	9,275	D
Restricted Stock Units	(1)	02/02/2026		M			7,775	(6)	(6)	Common Stock, par value $0.0001	7,775	$0	0	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. These shares were purchased due to participation by the reporting individual in the Issuer's 2019 Employee Stock Purchase Plan ("ESPP"). It pertains to the ESPP purchase period from August 1, 2025 through January 31, 2026.

4. In accordance with the ESPP, these shares were purchased based on 85% of the closing price of the Issuer's common stock on August 1, 2025.

5. The RSUs become vested in substantially equal annual installments over the 4 years following January 30, 2023, subject to the reporting person's continued service through the applicable vesting date, and have no expiration date.

6. The RSUs become vested in substantially equal annual installments over the 4 years following February 2, 2022, 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	02/03/2026
	** Signature of Reporting Person	Date
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FAQ

What insider activity did Altimmune (ALT) disclose for its Chief Scientific Officer?

Altimmune reported that Chief Scientific Officer Scot M. Roberts had RSUs vest into common stock, surrendered some shares for taxes, and bought shares through the 2019 Employee Stock Purchase Plan. Following these transactions, he directly held 112,824 shares of Altimmune common stock.

How many Altimmune shares vested from RSUs in the latest Form 4?

Two RSU blocks vested: 9,275 RSUs on January 30, 2026 and 7,775 RSUs on February 2, 2026. Each RSU converts into one share of common stock when vested, increasing the officer’s direct shareholdings before tax-related share surrenders.

Why were some Altimmune shares surrendered in these insider transactions?

The filing states that 2,859 shares on January 30, 2026 and 2,329 shares on February 2, 2026 were surrendered to Altimmune solely to cover taxes associated with RSU vesting. This is described as a vesting transaction for tax withholding purposes.

What did the Altimmune Form 4 reveal about ESPP purchases?

The Form 4 shows the officer purchased 5,567 shares of Altimmune common stock on January 31, 2026 through the 2019 Employee Stock Purchase Plan at $3.07 per share, equal to 85% of the stock’s closing price on August 1, 2025.

How many Altimmune shares does the reporting person own after these transactions?

After all reported RSU vesting, tax share surrenders, and ESPP purchases, the Chief Scientific Officer directly owned 112,824 shares of Altimmune common stock. The derivative table shows no remaining RSUs for these specific grants following the February 2, 2026 vesting.

How do the Altimmune RSUs vest according to the Form 4 footnotes?

The footnotes state each RSU equals one share of common stock upon vesting. One grant vests in substantially equal annual installments over four years following January 30, 2023, and another over four years following February 2, 2022, conditioned on continued service.