[Form 4/A] ASPEN AEROGELS INC Amended Insider Trading Activity

Rhea-AI Filing Summary

Aspen Aerogels filed an amended insider ownership report for its CFO and Treasurer following an equity grant. On October 1, 2025, the officer acquired 10,273 restricted stock units (RSUs) of common stock at a price of $0 per unit, reflecting a compensation award rather than an open-market purchase.

Each RSU represents one share of common stock and vests in three equal installments: one-third on March 5, 2026, one-third on March 5, 2027, and the final third on March 5, 2028. After correcting prior figures, the filing states the officer beneficially owns 25,392 share-based interests, consisting of 4,608 shares of common stock and 20,784 RSUs. The amendment explains that an earlier report had omitted 10,511 RSUs that were granted before the October 1, 2025 transaction date.

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

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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^*

Thoele Grant Douglas

(Last) (First) (Middle)

30 FORBES ROAD, BUILDING B

(Street)

NORTHBOROUGH MA 01532

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
ASPEN AEROGELS INC [ ASPN ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
10/01/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)
10/03/2025

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	10/01/2025		A		10,273(1)	A	$0	25,392(2)(3)	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

Explanation of Responses:

1. Each Restricted Stock Unit ("RSU") represents the right to receive one share of Common Stock upon vesting. The RSUs vest as to one-third of the shares on March 5, 2026, an additional one-third of the shares on March 5, 2027 and the remaining one-third of the shares on March 5, 2028.

2. This Form 4/A is being filed to correct the reported total of Securities Beneficially Owned following the reported transaction. The beneficially owned shares previously reported did not include 10,511 restricted stock units granted prior to the October 1, 2025, transaction date.

3. Represents 4,608 shares of Common Stock and 20,784 RSUs.

	/s/ Glenn Deegan, Attorney-in-Fact	12/19/2025
	** 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).
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