Terrestrial Energy CFO granted RSUs and options

Thrasher Brian Patrick reported acquisition or exercise transactions in this Form 4 filing.

Rhea-AI Filing Summary

Thrasher Brian Patrick reported acquisition or exercise transactions in this Form 4 filing.

Terrestrial Energy Inc. Chief Financial Officer Brian Patrick Thrasher received new equity awards as part of his compensation. He was granted 49,917 restricted stock units, each representing a contingent right to one share of common stock, and 58,236 stock options to buy common shares at $6.34 per share.

The restricted stock units and options were granted under the Terrestrial Energy Inc. 2025 Equity Incentive Plan. Both awards vest in one-third increments on each of the first, second, and third anniversaries of the grant date, conditioned on his continued service with the company. No open-market purchases or sales were reported in this filing.

Insider Trade Summary

Grant/Award: 108,153 shares

Grant/Award 2 txns

Insider Thrasher Brian Patrick

Role Chief Financial Officer

Type	Security	Shares	Price	Value
Grant/Award	Restricted Stock Units	49,917	$0.00	$0.00
Grant/Award	Stock Option (Right to Buy)	58,236	$0.00	$0.00

Holdings After Transaction: Restricted Stock Units — 49,917 contracts (Direct); Stock Option (Right to Buy) — 58,236 contracts (Direct)

Footnotes (3)

1. F1. Each restricted stock unit represents a contingent right to acquire one share of Common Stock.
2. F2. Consists of restricted stock units granted pursuant to the Terrestrial Energy Inc. 2025 Equity Incentive Plan. The restricted stock units vest in one-third increments on each of the first, second and third anniversaries of the grant date, subject to the reporting person's continued service through each applicable vesting date.
3. F3. Consists of options granted pursuant to the Terrestrial Energy Inc. 2025 Equity Incentive Plan. The options vest in one-third increments on each of the first, second and third anniversaries of the grant date, subject to the reporting person's continued service through each applicable vesting date.

Key Figures

RSU grant: 49,917 units Option grant: 58,236 options Option exercise price: $6.34 per share +3 more

6 metrics

RSU grant 49,917 units Restricted stock units granted to CFO; 1 RSU per common share

Option grant 58,236 options Stock options granted to CFO on common stock

Option exercise price $6.34 per share Strike price for 58,236 stock options

Option expiration 2036-04-12 Expiration date of stock options granted

RSUs after transaction 49,917 units Total restricted stock units held following grant

Options after transaction 58,236 options Total options held following grant

Key Terms

Restricted Stock Units, Stock Option (Right to Buy, 2025 Equity Incentive Plan, vesting

4 terms

Restricted Stock Units financial

"Each restricted stock unit represents a contingent right to acquire one share of Common Stock."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Stock Option (Right to Buy financial

"Consists of options granted pursuant to the Terrestrial Energy Inc. 2025 Equity Incentive Plan."

2025 Equity Incentive Plan financial

"Consists of restricted stock units granted pursuant to the Terrestrial Energy Inc. 2025 Equity Incentive Plan."

vesting financial

"The restricted stock units vest in one-third increments on each of the first, second and third anniversaries of the grant date."

Vesting is the process by which you earn full ownership of something, like company stock or a retirement benefit, over time. It’s like earning the right to keep a gift piece by piece the longer you stay with a company, making sure employees stay committed before they receive all the benefits.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What equity awards did Terrestrial Energy (IMSR) CFO Brian Thrasher receive?

Brian Patrick Thrasher received 49,917 restricted stock units and 58,236 stock options. The options allow him to buy common shares at $6.34 each, reflecting a compensation grant rather than an open-market share purchase or sale.

Are the new IMSR CFO equity awards from a company incentive plan?

Yes. Both the 49,917 restricted stock units and 58,236 stock options were granted under the Terrestrial Energy Inc. 2025 Equity Incentive Plan, aligning the Chief Financial Officer’s compensation with shareholder interests through stock-based incentives over time.

How do Brian Thrasher’s Terrestrial Energy (IMSR) RSUs vest?

The 49,917 restricted stock units vest in three equal installments. One-third vests on each of the first, second, and third anniversaries of the grant date, provided Brian Thrasher continues to serve the company through each applicable vesting date.

What are the terms of the IMSR stock options granted to the CFO?

The 58,236 stock options have a $6.34 exercise price and expire in 2036. They vest in one-third increments on each of the first, second, and third anniversaries of the grant date, contingent on Brian Thrasher’s continued service with Terrestrial Energy Inc.

Did the IMSR CFO buy or sell shares in the market in this Form 4?

No market trades were reported. The Form 4 only shows compensation-related grants of restricted stock units and stock options. There were no open-market purchases or sales of Terrestrial Energy Inc. common stock by the Chief Financial Officer in this filing.

How many Terrestrial Energy (IMSR) RSUs and options does the CFO hold after these grants?

After the grants, Brian Thrasher holds 49,917 restricted stock units and 58,236 stock options related to common stock. These positions reflect the new awards reported and are subject to the stated vesting schedules and service-based conditions.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 04/14/2026 - 06:00 PM EDT Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Thrasher Brian Patrick

(Last) (First) (Middle)

C/O TERRESTRIAL ENERGY INC.

2730 W. TYVOLA ROAD, SUITE 100

(Street)

CHARLOTTE NORTH CAROLINA 28217

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Terrestrial Energy Inc. /DE/ [ IMSR ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/12/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Units	(1)	04/12/2026		A		49,917		(2)	(2)	Common Stock	49,917	$0	49,917	D
Stock Option (Right to Buy)	$6.34	04/12/2026		A		58,236		04/12/2027(3)	04/12/2036	Common Stock	58,236	$0	58,236	D

Explanation of Responses:

1. Each restricted stock unit represents a contingent right to acquire one share of Common Stock.

2. Consists of restricted stock units granted pursuant to the Terrestrial Energy Inc. 2025 Equity Incentive Plan. The restricted stock units vest in one-third increments on each of the first, second and third anniversaries of the grant date, subject to the reporting person's continued service through each applicable vesting date.

3. Consists of options granted pursuant to the Terrestrial Energy Inc. 2025 Equity Incentive Plan. The options vest in one-third increments on each of the first, second and third anniversaries of the grant date, subject to the reporting person's continued service through each applicable vesting date.

	/s/ Steven M. Millsap, Attorney-in-Fact	04/14/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)