Altimmune (NASDAQ: ALT) CSO exercises RSUs, surrenders shares for tax

Rhea-AI Filing Summary

Altimmune Chief Scientific Officer Scot Roberts reported equity compensation activity involving company stock. On January 27, 2026, he converted 15,850 Restricted Stock Units into an equal number of Altimmune common shares at $0 per share, reflecting standard RSU settlement. In a related tax withholding step, 4,748 shares were surrendered to Altimmune at $6.18 per share to cover taxes due on the vesting. Following these transactions, Roberts directly owned 95,395 shares of common stock and 47,550 RSUs, which each represent a right to receive one share of common stock as they vest over time.

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)
01/27/2026

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	01/27/2026		M		15,850	A	$0(1)	100,143	D
Common Stock, par value $0.0001	01/27/2026		F(2)		4,748	D	$6.18	95,395	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)	01/27/2026		M			15,850	(3)	(3)	Common Stock, par value $0.0001	15,850	$0	47,550	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 27, 2025, 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	01/29/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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FAQ

What insider transaction did Altimmune (ALT) report for Scot Roberts?

Altimmune reported that Chief Scientific Officer Scot Roberts converted 15,850 RSUs into common stock and surrendered 4,748 shares to cover taxes. These transactions are part of equity compensation vesting rather than an open-market discretionary sale.

How many Altimmune (ALT) shares does Scot Roberts hold after this Form 4?

After the reported transactions, Scot Roberts directly holds 95,395 shares of Altimmune common stock. He also holds 47,550 Restricted Stock Units, each representing a contingent right to receive one share of common stock when it vests.

What does the 15,850 RSU conversion mean for Altimmune (ALT)?

The conversion of 15,850 RSUs into common stock reflects previously granted equity awards vesting for Altimmune’s Chief Scientific Officer. It is a compensation-related event, not a new grant, and follows the terms of his RSU award agreement.

Why were 4,748 Altimmune (ALT) shares surrendered at $6.18?

The 4,748 shares were surrendered to Altimmune at $6.18 per share solely to cover taxes triggered by RSU vesting. This tax withholding method avoids the executive paying cash while satisfying required tax obligations.

How do Scot Roberts’ Altimmune (ALT) RSUs vest over time?

The RSUs vest in substantially equal annual installments over four years following January 27, 2025, subject to his continued service. The units have no expiration date and each RSU converts into one share of common stock when vested.

Is the reported Altimmune (ALT) insider activity an open-market sale?

No. The filing shows RSU conversion at $0 and a tax withholding transaction where shares were surrendered back to Altimmune. It does not report a discretionary open-market sale into the public market.