IMSR insider Form 3: options, warrants, and 11.18M exchangeables

Rhea-AI Filing Summary

Terrestrial Energy Inc. (IMSR) disclosed an initial statement of beneficial ownership for its Chief Technology Officer and Director. The filing reports 5,981 shares of Common Stock held directly and 13,731 shares held indirectly through an entity.

Derivative holdings include stock options currently exercisable for 17,792 shares (expiring 06/16/2038 at $2.0133), and options for 53,197 shares (expiring 01/01/2043 at $2.237), 63,836 shares (expiring 01/01/2044 at $2.237), and 10,640 shares (expiring 01/01/2045 at $2.237). The report also lists 11,175,778 exchangeable shares of a subsidiary that are exchangeable for Common Stock with no expiration date, warrants for 17,882 shares (direct) and 41,575 shares (indirect) at $2.237 expiring 07/31/2028, and contingent value rights tied to a $7.905 redemption price and a 75% VWAP condition after the lock-up period.

The holdings reflect securities received in connection with the business combination between HCM II Acquisition Corp. and Legacy Terrestrial, effective for the reporting date of 10/28/2025.

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^*

LeBlanc David Michael

(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
X	Officer (give title below)		Other (specify below)
	Chief Technology Officer

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")	5,981(1)	D
Common Stock	13,731(1)	I	Through Entity

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)	06/16/2038	Common Stock	17,792	$2.0133	D
Stock Option (Right to Buy)	(2)	01/01/2043	Common Stock	53,197	$2.237	D
Stock Option (Right to Buy)	(2)	01/01/2044	Common Stock	63,836	$2.237	D
Stock Option (Right to Buy)	(2)	01/01/2045	Common Stock	10,640	$2.237	D
Exchangeable Shares	(3)	(3)	Common Stock	11,175,778	(3)	D
Warrants (Right to Buy)	(4)	07/31/2028	Common Stock	17,882	$2.237	D
Warrants (Right to Buy)	(4)	07/31/2028	Common Stock	41,575	$2.237	I	Through Entity
Contingent Value Right	(5)	(5)	Common Stock	(5)	(5)	D
Contingent Value Right	(5)	(5)	Common Stock	(5)	(5)	I	Through Entity

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 are currently exercisable.

3. Represents exchangeable shares in the capital of Terrestrial Energy Canada (Exchange) Inc., an indirect wholly-owned subsidiary of New Terrestrial, which are exchangeable for Common Stock of New Terrestrial, subject to adjustment. The exchangeable shares have no expiration 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).
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FAQ

What did Terrestrial Energy Inc. (IMSR) disclose in this Form 3?

An initial statement of beneficial ownership for the CTO/Director, including direct and indirect Common Stock, options, warrants, exchangeable shares, and contingent value rights.

How many Terrestrial Energy Common Stock shares are owned directly and indirectly?

Direct ownership is 5,981 shares; indirect ownership is 13,731 shares through an entity.

What derivative securities are reported and their key terms?

Exercisable options for 17,792, 53,197, 63,836, and 10,640 shares with exercise prices of $2.0133 and $2.237, expiring between 2038 and 2045.

How many exchangeable shares are reported and what is their feature?

There are 11,175,778 exchangeable shares, exchangeable for Common Stock with no expiration date.

What warrants are included in the filing?

Warrants for 17,882 shares (direct) and 41,575 shares (indirect) at $2.237 per share, expiring on 07/31/2028.

What triggers the contingent value rights (CVRs)?

Each CVR pays additional shares if the 20-day VWAP after the lock-up is less than 75% of the $7.905 redemption price.

What is the event date for this ownership report?

The reported event date is 10/28/2025.