Grant Douglas Thoele - 01 Oct 2025 Form 3/A - Amendment Insider Report for ASPEN AEROGELS INC (ASPN)

Role: CFO & Treasurer
Signature: /s/ Glenn Deegan, Attorney-in-Fact
Issuer symbol: ASPN
Transactions as of: 01 Oct 2025
Net transactions value: $0
Form type: 3/A - Amendment
Filing time: 19 Dec 2025, 17:00:04 UTC
Date Of Original Report: 02 Oct 2025
Next filing: 06 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Thoele Grant Douglas	CFO & Treasurer	30 FORBES ROAD, BUILDING B, NORTHBOROUGH	/s/ Glenn Deegan, Attorney-in-Fact	19 Dec 2025	0002089743

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
holding	ASPN	Common Stock						15,119	01 Oct 2025	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	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.
F2	The unvested RSUs described in footnote 1 were inadvertently omitted from the reporting person's original Form 3.

Content

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.

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