IMSR director’s initial ownership: two option grants disclosed on Form 3

Rhea-AI Filing Summary

Terrestrial Energy Inc. (IMSR) filed a Form 3 reporting a director’s initial beneficial ownership as of 10/28/2025. The filing lists stock options for 22,352 shares at $2.237 expiring on 12/03/2044 and 44,703 shares at $7.8295 expiring on 05/19/2045. These options were granted under the Second Amended and Restated 2024 Stock Option Plan and vest in one‑third increments on each of the first, second, and third anniversaries of the grant date, subject to continued service.

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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

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1. Name and Address of Reporting Person^*

Jones Robert Wood

(Last) (First) (Middle)

2730 W. TYVOLA ROAD, SUITE 100

(Street)

CHARLOTTE NC 28217

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
10/28/2025

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

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

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

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

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

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

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (Right to Buy)	12/05/2025(1)	12/03/2044	Common Stock	22,352	$2.237	D
Stock Option (Right to Buy)	05/19/2026(1)	05/19/2045	Common Stock	44,703	$7.8295	D

Explanation of Responses:

1. Consists of options granted pursuant to the Terrestrial Energy Inc. Second Amended and Restated 2024 Stock Option 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.

Remarks:

Exhibit List - Exhibit 24.1 - Power of Attorney

	/s/ Steven M. Millsap, pursuant to Power of Attorney	11/07/2025
	** 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 5 (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.

FAQ

What did Terrestrial Energy Inc. (IMSR) file?

A Form 3 disclosing a director’s initial beneficial ownership, including stock options granted under the 2024 Stock Option Plan.

What derivative securities are reported for IMSR?

Stock options for 22,352 shares at $2.237 expiring 12/03/2044 and 44,703 shares at $7.8295 expiring 05/19/2045.

When do the reported IMSR options become exercisable?

One grant is exercisable on 12/05/2025; the other becomes exercisable on 05/19/2026.

What is the vesting schedule for the IMSR options?

They vest in one‑third increments on each of the first, second, and third anniversaries of the grant date, subject to continued service.

Under which plan were the IMSR options granted?

The Terrestrial Energy Inc. Second Amended and Restated 2024 Stock Option Plan.

What is the relationship of the reporting person to IMSR?

The reporting person is a Director.