Simon Irish, Chief Executive Officer and Director of Terrestrial Energy Inc. /DE/ (NASDAQ:IMSR), filed a Form 4 on October 30, 2026, reporting an October 28, 2026 conversion of 55,432 restricted stock units into common stock at a price of $0.

Key Highlights

  • Transaction: Irish acquired 55,432 shares of common stock on October 28, 2026, via transaction code M (exercise/conversion of derivative security), at a price of $0.
  • RSU balance after transaction: Irish directly holds 110,866 restricted stock units following the reported transaction.
  • Direct common stock ownership: Irish directly holds 2,879,846 shares of common stock following the transaction.
  • Indirect holdings: Irish also holds 2,818,520 shares indirectly through an LLC and 52,255 shares through an IRA.
  • RSU vesting schedule: According to the filing, the restricted stock units vest pro rata over a three-year period following the grant date, subject to Irish's continued employment through each applicable vesting date and accelerated vesting in certain events.
  • Filing signatory: The form was signed by Brian Thrasher as attorney-in-fact on October 30, 2026.

Simon Irish RSU Conversion Details at Terrestrial Energy Inc.

According to the Form 4 filed with the U.S. Securities and Exchange Commission, Simon Irish, who serves as both Chief Executive Officer and Director of Terrestrial Energy Inc. /DE/ (NASDAQ:IMSR), reported a change in beneficial ownership resulting from the vesting and conversion of restricted stock units. The transaction occurred on October 28, 2026, and the filing was submitted on October 30, 2026.

The filing discloses that 55,432 restricted stock units were converted into 55,432 shares of common stock at a conversion price of $0. The filing states that these shares represent "shares of common stock subject to vested portion of restricted stock unit award" and that "each restricted stock unit represents a contingent right to receive one share of common stock." Following this transaction, Irish directly holds 2,879,846 shares of common stock. He also holds shares indirectly: 2,818,520 through an LLC and 52,255 through an IRA.

In the derivative securities table, the filing records that Irish's remaining directly held restricted stock unit balance stands at 110,866 units after the transaction. The filing notes that the RSUs vest pro rata over a three-year period following the grant date, subject to Irish's continued employment through each applicable vesting date, with accelerated vesting available in certain events. The form was filed by one reporting person and was signed by Brian Thrasher as attorney-in-fact.

What Was Disclosed

Terrestrial Energy Inc. /DE/ (NASDAQ:IMSR) CEO Simon Irish reported the October 28, 2026 conversion of 55,432 vested restricted stock units into common stock at $0, resulting in direct ownership of 2,879,846 common shares and a remaining RSU balance of 110,866 units.