IMSR director reports holdings: common stock, options, warrants, CVR

Rhea-AI Filing Summary

Terrestrial Energy Inc. disclosed an initial statement of beneficial ownership by a director. The filing reports 18,470 shares of Common Stock held directly.

The director also holds derivative securities: stock options for 447,030 shares at $0.2013 (CAD) expiring 06/01/2034 and 67,055 shares at $1.1185 (CAD) expiring 02/01/2036, both currently exercisable; an option for 67,055 shares vesting in thirds from 04/01/2024 and expiring 04/01/2043; and 55,879 warrants at $2.237 expiring 07/31/2028. A contingent value right may deliver additional shares if the 20‑day VWAP after the lock-up period is below 75% of the $7.905 redemption price.

These holdings reflect securities received in exchange at the closing of a business combination between HCM II Acquisition Corp. and Terrestrial Energy Development Inc.

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^*

Hill David John

(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")	18,470(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)	06/01/2034	Common Stock	447,030	$0.2013(6)	D
Stock Option (Right to Buy)	(2)	02/01/2036	Common Stock	67,055	$1.1185(6)	D
Stock Option (Right to Buy)	04/01/2024(3)	04/01/2043	Common Stock	67,055	$2.237	D
Warrants (Right to Buy)	(4)	07/31/2028	Common Stock	55,879	$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 are currently exercisable.

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).

6. Price is expressed in Canadian dollars.

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) disclose in this Form 3?

A director reported 18,470 Common Stock shares held directly and multiple derivative positions, including options, warrants, and a contingent value right.

How many stock options were reported and at what terms?

Options for 447,030 shares at $0.2013 (CAD, exp. 06/01/2034), 67,055 shares at $1.1185 (CAD, exp. 02/01/2036), and 67,055 shares vesting in thirds from 04/01/2024 (exp. 04/01/2043).

What warrants were disclosed by the director?

55,879 warrants to purchase Common Stock at an exercise price of $2.237, expiring on 07/31/2028.

What triggers the contingent value right (CVR)?

The CVR grants additional shares if the 20‑day VWAP after the lock-up period is under 75% of the $7.905 redemption price.

When is the event date for this Form 3?

The reported event date is 10/28/2025.

What is the reporting person’s relationship to Terrestrial Energy Inc.?

The reporting person is a Director.

How were the reported securities acquired?

They were received in exchange at the closing of a business combination involving HCM II Acquisition Corp. and Terrestrial Energy Development Inc.