Terrestrial Energy Inc. /DE/ (IMSR) IPO — S-1 Filing, Stock & Insider Activity

Terrestrial Energy Inc. /DE/ IPO — Status & S-1 Filing

Ticker: IMSR
Status: Registered — S-1 filed with the SEC
S-1 filed: 2025-11-26
Exchange: NASDAQ
Expected price range: not yet disclosed (set in a later S-1/A or pricing amendment)
Shares offered: 18,776,119
SEC CIK: 0002019804 · View the S-1 on SEC EDGAR →

Terrestrial Energy Inc. /DE/ is pre-IPO, so no insider Form 4 transactions have been filed yet. Once insiders begin reporting trades after the offering, they will appear on this page automatically.

Track every registration update on the InsiderAlpha IPO tracker.

Updated Jul 17, 2026 · Last SEC filing 2026-04-14

Terrestrial Energy Inc. /DE/ (IMSR) — no SEC Form 4 insider filings recorded in the last 90 days. 3 Form 8-K material event filings were reported by IMSR in the last 90 days. InsiderAlpha tracks every IMSR SEC filing — Form 4, Form 144, and 8-K — in real time, including Rule 10b5-1 plan detection.

About Terrestrial Energy Inc. /DE/ (IMSR)

SEC CIK	0002019804

90-Day SEC Filing Activity

Form 8-K filings (90d)	3
Latest Form 4 filing	2026-04-14

Recent IMSR Insider Transactions (Form 4)

Date	Insider	Role	Transaction	Shares	Price	Value	Filing
2025-11-06	Matthews Shawn	Director	J — Other acquisition / disposition	2.92M	—	—	SEC
2025-10-28	Brenner Andrew Scott	Insider	J — Other acquisition / disposition	25.0K	—	—	SEC
2025-10-28	Loveless Jacob	Insider	J — Other acquisition / disposition	25.0K	—	—	SEC
2025-10-28	Connor Michael J	Insider	J — Other acquisition / disposition	25.0K	—	—	SEC
2025-10-28	Matthews Shawn	Director	J — Other acquisition / disposition	5.67M	—	—	SEC
2025-10-28	Matthews Shawn	Director	J — Other acquisition / disposition	533.5K	—	—	SEC

All transactions sourced from SEC EDGAR Form 4 filings for Terrestrial Energy Inc. /DE/ (IMSR). Updated in real time as new filings are submitted to the SEC.

Recent IMSR Form 8-K Material Events

2026-06-12 — Item 5.07 [SEC]
2026-05-14 — Item 2.02, 9.01 [SEC]
2026-05-08 — Item 5.02 [SEC]
2026-04-16 — Item 5.02, 9.01 · Leadership · neutral [SEC]
Terrestrial Energy Inc. entered into new employment agreements with certain executive officers on April 16, 2026, replacing prior agreements. The filing details the compensation and benefits for CFO Brian Thrasher, including a $350,000 annual base salary, bonus eligibility with 4
2026-03-30 — Item 2.02, 9.01 · Earnings · neutral [SEC]
Terrestrial Energy Inc. announced its financial and operating results for the year and quarter ended December 31, 2025 on March 30, 2026. The filing provides standard periodic financial results without indication of beat, miss, or guidance changes.

Recent Insider Filings

2026-04-14 — Millsap Steven M. (General Counsel)
2026-04-14 — Thrasher Brian Patrick (Chief Financial Officer)
2026-04-14 — Smith William F. (Chief Operating Officer)
2026-04-14 — LeBlanc David Michael (Chief Technology Officer)
2026-01-09 — JOHNSON WILLIAM D (Director)

Form 4 Transaction Code Reference

SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in IMSR insider filings:

P	Open-market purchase by the insider
S	Open-market sale by the insider
A	Grant, award, or other acquisition from the issuer
M	Exercise or conversion of derivative security (e.g. options)
F	Payment of exercise price or tax liability via share withholding
G	Bona-fide gift of securities
D	Disposition to the issuer (e.g. share buyback participation)
J	Other acquisition or disposition
X	Exercise of in-the-money or at-the-money derivative security
C	Conversion of derivative security
V	Transaction voluntarily reported earlier than required

IMSR Insider Trading — FAQ

What is the latest insider trade for IMSR?: Terrestrial Energy Inc. /DE/ (IMSR) had 0 insider filings in the last 90 days, with the most recent on 2026-04-14. InsiderAlpha tracks every Form 4, 10-K, 10-Q, and 8-K filing in real time.
How many insiders are buying IMSR stock?: 0 insider purchases of IMSR were filed in the last 90 days.
How many insiders are selling IMSR stock?: 0 insider sales of IMSR were filed in the last 90 days.
Where can I see IMSR SEC filings (Form 4, 10-K, 10-Q, 8-K)?: InsiderAlpha aggregates every IMSR SEC filing — Form 4 insider transactions, 10-K and 10-Q quarterly reports, and 8-K material event disclosures — in one timeline.

Learn More

Open the live IMSR dashboard on InsiderAlpha for real-time alerts, charting, and full historical filing search.