[Form 3/A] ASPEN AEROGELS INC Amended Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

Aspen Aerogels filed an amended insider ownership report for its CFO and Treasurer. The filing shows that the officer beneficially owns 15,119 shares of common stock, including 4,608 shares of common stock and 10,511 restricted stock units (RSUs). The RSUs were granted on March 8, 2023, March 5, 2024, and March 5, 2025, with various time-based vesting schedules extending through March 5, 2028. The amendment clarifies that these unvested RSUs had been inadvertently omitted from the reporting person’s original filing.

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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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. Date of Event Requiring Statement (Month/Day/Year)
10/01/2025

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

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

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

5. If Amendment, Date of Original Filed (Month/Day/Year)
10/02/2025

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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	15,119(1)(2)	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Represents 4,608 shares of common stock and 10,511 restricted stock units ("RSUs"), including (i) 1,687 RSUs that were granted on March 8, 2023 and vesting on March 8, 2026, (ii) 2,447 RSUs that were granted on March 5, 2024 and vesting equally on March 5, 2026 and March 5, 2027, and (iii) 6,377 RSUs that were granted on March 5, 2025 and vesting as to one-third of the shares on each anniversary of the grant date until March 5, 2028.

2. The unvested RSUs described in footnote 1 were inadvertently omitted from the reporting person's original Form 3.

	/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 5 (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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