| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| Thoele Grant Douglas | CFO & Treasurer | C/O ASPEN AEROGELS, INC.,, 30 FORBES ROAD, BUILDING B, NORTHBOROUGH | /s/ Glenn Deegan, Attorney-in-Fact | 10 Mar 2026 | 0002089743 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | ASPN | Common Stock | Tax liability | -590 | -0.75% | $3.22* | 77,732 | 08 Mar 2026 | Direct | F1, F2 |
| Id | Content |
|---|---|
| F1 | Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs"). |
| F2 | Represents 10,111 shares of Common Stock and 67,621 RSUs. |