IMSR director files Form 3 with 6,758 shares, options and warrants

Rhea-AI Filing Summary

Terrestrial Energy Inc. (IMSR) filed an initial Form 3 for a director, reporting beneficial ownership as of 10/28/2025, following the closing of the business combination between the former HCM II Acquisition Corp. and Legacy Terrestrial, where securities were received in exchange for Legacy holdings.

The director holds 6,758 shares of Common Stock directly. Reported derivatives include stock options for 178,812 shares at $2.0133 expiring 06/09/2039 (milestone-based vesting), options for 67,055 shares at $2.237 expiring 04/01/2043 (vesting one-third annually over three years), options for 134,109 shares at $2.237 expiring 04/24/2044 (same vesting), and warrants for 22,352 shares at $2.237 expiring 07/31/2028. A contingent value right may deliver additional shares if the 20-day VWAP after the lock-up is less than 75% of the $7.905 redemption price.

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^*

Pardee Charles G

(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)
Common Stock, par value $0.0001 per share ("Common Stock")	6,758(1)	D

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)	(2)	06/09/2039	Common Stock	178,812	$2.0133	D
Stock Option (Right to Buy)	04/01/2024(3)	04/01/2043	Common Stock	67,055	$2.237	D
Stock Option (Right to Buy)	04/24/2025(3)	04/24/2044	Common Stock	134,109	$2.237	D
Warrants (Right to Buy)	(4)	07/31/2028	Common Stock	22,352	$2.237	D
Contingent Value Right	(5)	(5)	Common Stock	(5)	(5)	D

Explanation of Responses:

1. Upon closing of the business combination (the "Business Combination") between Terrestrial Energy Inc., a Delaware corporation formerly known as HCM II Acquisition Corp. ("New Terrestrial"), and Terrestrial Energy Development Inc., a Delaware corporation formerly known as Terrestrial Energy Inc. ("Legacy Terrestrial"), the reporting person acquired these securities in exchange for the reporting person's securities in Legacy Terrestrial pursuant to the terms and conditions of the Business Combination Agreement, dated as of March 26, 2025, by and among HCM II Acquisition Corp., HCM II Merger Sub Inc. and Legacy Terrestrial.

2. Consists of options granted pursuant to the Legacy Terrestrial Second Amended and Restated 2024 Stock Option Plan. The options vest on certain specified milestone conditions.

3. Consists of options granted pursuant to the Legacy Terrestrial 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.

4. Consists of Legacy Terrestrial warrants to purchase common stock that are currently exercisable.

5. Consists of contingent value right issued upon conversion of Legacy Terrestrial convertible notes in connection with the Business Combination. Each contingent value right entitles the holder to receive additional shares of Common Stock in the event that the volume weighed average price of the Common Stock for the twenty (20) trading days beginning on the trading day immediately following expiration of the lock-up period contemplated by the applicable Legacy Terrestrial convertible note is less than seventy-five percent (75%) of the redemption price ($7.905).

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 (IMSR) disclose in this Form 3?

A director reported initial beneficial ownership, including 6,758 common shares, multiple stock options, warrants, and a contingent value right.

How many Terrestrial Energy common shares does the director own?

The filing lists 6,758 shares of Common Stock held directly.

What stock options are reported by the IMSR director?

Options for 178,812 at $2.0133 (exp. 06/09/2039), 67,055 at $2.237 (exp. 04/01/2043), and 134,109 at $2.237 (exp. 04/24/2044), with stated vesting terms.

What warrants are disclosed in the Form 3 for IMSR?

The filing shows warrants for 22,352 shares at $2.237 expiring 07/31/2028.

What is the contingent value right (CVR) described?

Each CVR may deliver additional shares if the 20-day VWAP after the lock-up is under 75% of $7.905.

How were these securities acquired?

They were received in exchange for Legacy Terrestrial securities at the closing of the business combination with the former HCM II Acquisition Corp.

What is the filer’s relationship to Terrestrial Energy?

The reporting person is a Director and filed individually.