Donald R. Young - 04 Mar 2026 Form 4 Insider Report for ASPEN AEROGELS INC (ASPN)

Role: President and CEO, Director
Signature: /s/ Glenn Deegan, Attorney-in-Fact
Issuer symbol: ASPN
Transactions as of: 04 Mar 2026
Net transactions value: $0
Form type: 4
Filing time: 06 Mar 2026, 17:00:29 UTC
Previous filing: 14 Nov 2025
Next filing: 10 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Young Donald R	President and CEO, Director	C/O ASPEN AEROGELS, INC.,, 30 FORBES ROAD, BLDG B, NORTHBOROUGH	/s/ Glenn Deegan, Attorney-in-Fact	06 Mar 2026	0001610257

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	ASPN	Common Stock	Award		+156,716	+32%	$0.000000^*	650,727	04 Mar 2026	Direct	F1
transaction	ASPN	Common Stock	Tax liability		-8,618	-1.3%	$3.27^*	642,109	05 Mar 2026	Direct	F2, F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	ASPN	Stock Options (Right to Buy)	Award		+212,249		$0.000000^*	212,249	04 Mar 2026	Common Stock	212,249	$3.35	Direct	F4

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

Explanation of Responses:

Id	Content
F1	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 4, 2027, an additional one-third of the shares on March 4, 2028 and the remaining one-third of the shares on March 4, 2029.
F2	Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").
F3	Represents 430,387 shares of Common Stock and 211,722 RSUs.
F4	The options vest as to one-third of the shares on March 4, 2027, an additional one-third of the shares on March 4, 2028 and the remaining one-third of the shares on March 4, 2029.