Terrestrial Energy Inc. (IMSR)
Nasdaq: IMSR · Fabricated Plate Work (Boiler Shops) · Charlotte, NC · filing with the SEC since 2024
Who runs Terrestrial Energy Inc.
Officers and directors as they report to the SEC on Forms 3, 4 and 5, named as filedChief executive, as filed
Irish Simon
Chief Executive Officer. First filing Oct 2025, latest Oct 30, 2026, 1 filing in all.
Officers reporting now
8
of 18 people with a filing in the last fifteen months
Directors reporting now
10
19 people on the record since 2024
Officerssales are open-market, Oct 30, 2025 to Oct 30, 2026
| Name | Title as filed | First filing | Latest filing | Sales, 12 months |
|---|---|---|---|---|
| Irish Simon | Chief Executive Officer | Oct 2025 | Oct 30, 2026 | none |
| Williams David Woodward | Chief Commercial Officer | Oct 2026 | Oct 21, 2026 | none |
| Cowan Pamela Beth | EVP, Engineering | Jul 2026 | Jul 31, 2026 | none |
| Thrasher Brian Patrick | Chief Financial Officer | Nov 2025 | Apr 14, 2026 | none |
| Smith William F. | Chief Operating Officer | Nov 2025 | Apr 14, 2026 | none |
| Leblanc David Michael | Chief Technology Officer | Nov 2025 | Apr 14, 2026 | none |
| Millsap Steven M. | General Counsel | Nov 2025 | Apr 14, 2026 | none |
| Matthews Shawn | Chairman and CEO | Aug 2024 | Dec 22, 2025 | none |
Directorssales are open-market, Oct 30, 2025 to Oct 30, 2026
| Name | Role | First filing | Latest filing | Sales, 12 months |
|---|---|---|---|---|
| Pardee Charles G | director | Nov 2025 | Oct 15, 2026 | none |
| Buckman Frederick W | director | Nov 2025 | Oct 13, 2026 | none |
| Mccarthy Kathryn Ann | director | Jul 2026 | Jul 27, 2026 | none |
| Johnson William D | director | Nov 2025 | Jan 9, 2026 | none |
| Hill David John | director | Nov 2025 | Dec 22, 2025 | none |
| Jones Robert Wood | director | Nov 2025 | Dec 22, 2025 | none |
| Macdiarmid John Hugh | director | Nov 2025 | Dec 22, 2025 | none |
| Brenner Andrew Scott | director | Aug 2024 | Oct 30, 2025 | none |
| Connor Michael J | director | Aug 2024 | Oct 30, 2025 | none |
| Loveless Jacob | director | Aug 2024 | Oct 30, 2025 | none |
Owners of more than 10% of a classsales are open-market, Oct 30, 2025 to Oct 30, 2026
| Name | Role | First filing | Latest filing | Sales, 12 months |
|---|---|---|---|---|
| Sella Roberto Marco | 10% owner | Jan 2026 | Feb 17, 2026 | none |
| Hcm Investor Holdings II, LLC | 10% owner | Aug 2024 | Nov 13, 2025 | none |
Earlier names on the record1, newest filing first
A person is listed as reporting now after a filing in the last fifteen months. The record shows when someone last filed; it does not say why they stopped. Each name links to the filings on sec.gov.