ASPN · Aspen Aerogels Inc

Represents 103,786 shares of Common Stock and 10,370 Restricted Stock Units.

These stock options were fully vested and exercisable.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

Represents 12,246 shares of Common Stock and 10,370 RSUs.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

Represents 88,987 shares of Common Stock and 10,370 RSUs.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

Represents 23,953 shares of Common Stock and 10,370 RSUs.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

Represents 25,951 shares of Common Stock and 10,370 RSUs.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

Represents 146,528 shares of Common Stock and 10,370 RSUs.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) May 13, 2027, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2027.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 26,317 shares of Common Stock and 76,614 RSUs.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 10,111 shares of Common Stock and 67,621 RSUs.

1. Shares withheld by Registrant to satisfy minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 438,349 shares of Common Stock and 199,485 RSUs.

1. Shares withheld by Registrant to satisfy minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 128,170 shares of Common Stock and 77,145 RSUs.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 22,735 shares of Common Stock and 82,120 RSUs.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 124,588 shares of Common Stock and 82,651 RSUs.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 9,014 shares of Common Stock and 69,308 RSUs.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 5,593 shares of Common Stock and 9,737 RSUs.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 430,387 shares of Common Stock and 211,722 RSUs.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Represents 67,176 RSUs.

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.

The transaction reported on this Form 4 was effected pursuant to a rule 10b5-1 trading plan. This plan was previously adopted by the reporting person on August 11, 2025, to sell a limited number of shares for tax purposes in connection with a one-time personal real estate transaction.

These transactions were executed in multiple trades at prices ranging from $3.15 to $3.41. The reporting person will provide to the staff of the Securities and Exchange Commission, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price.

Represents 414,306 shares of Common Stock and 79,705 Restricted Stock Units.

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.

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.

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

Each performance share unit ("PSU") represents a contingent right to receive one share of Common Stock upon vesting. The PSUs vest on March 5, 2028, following the completion of the performance period, which begins on January 1, 2025 and ends on December 31, 2027. Ranging between 0-200% of the target number of PSUs (as reflected in Table II above), the PSUs vest based on the total shareholder return of Common Stock relative to the total stockholder return of the components of the Russell 2000 Index.

The options vest as to one-third of the shares on September 30, 2026, an additional one-third of the shares on September 30, 2027 and the remaining one-third of the shares on September 30, 2028.

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 September 30, 2026, an additional one-third of the shares on September 30, 2027 and the remaining one-third of the shares on September 30, 2028.

Represents 11,673 RSUs.

1. Shares withheld by Registrant to satisfy minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

2. Represents 3,761 shares of Common Stock and 12,555 RSUs.

1. Shares withheld by Registrant to satisfy minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

2. Represents 9,196 shares of Common Stock and 33,061 RSUs.

Represents 17,879 Restricted Stock Units.

These transactions were executed in multiple trades at prices ranging from $7.31 to $7.32. The reporting person will provide to the staff of the Securities and Exchange Commission, the issuer, or any security holder of the issuer, upon request, full information regarding the number of shares sold at each separate price.

The vesting of the restricted stock units was accelerated upon the Reporting Person's termination of employment on May 23, 2025. The accelerated vesting was in accordance with the terms of the Reporting Person's Executive Agreement, which provides for acceleration upon termination under certain circumstances.

Shares withheld by Registrant to satisfy the minimum statutory tax withholding requirements on vesting of Restricted Stock Units ("RSUs").

Represents 24,235 shares of Common Stock and 20,215 RSUs.

Represents 471,151 shares of Common Stock and 79,705 RSUs.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.

Represents 15,581 shares of Common Stock and 10,370 RSUs.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.

Represents 1,876 shares of Common Stock and 10,370 RSUs.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.

The reporting person was granted Restricted Stock Units ("RSUs") representing a portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.

Represents 136,158 shares of Common Stock and 10,370 RSUs

The reporting person was granted options representing the remaining portion of the annual grant of equity for service as a non-employee director pursuant to the Issuer's Non-Employee Director Compensation Policy. The options will vest on the earlier of (a) April 30, 2026, or (b) the day prior to the Issuer's annual meeting of stockholders to be held in 2026.