Simon Irish - 28 Oct 2025 Form 3 Insider Report for Terrestrial Energy Inc. /DE/ (HOND)

Reporting relationship
Chief Executive Officer, Director
Issuer ticker
HOND
Reported as of
28 Oct 2025
Net transaction value
$0
Source evidence Original filing metadata and source links for verification. 3 source fields
SEC form
3
Accepted by SEC
07 Nov 2025, 18:33:18 UTC
Source filing
View source filing
Reporting owner 1 detail
Reporting owner signature
/s/ Steven M. Millsap, pursuant to Power of Attorney

Key filing fact

Simon Irish filed Form 3 for Terrestrial Energy Inc. /DE/ (HOND) on 07 Nov 2025.

Key facts

  • This page summarizes Simon Irish's Form 3 filing for Terrestrial Energy Inc. /DE/ (HOND).
  • 0 reported transactions and 17 derivative rows are listed below.
  • Accepted by SEC: 07 Nov 2025, 18:33.

Change

  • No earlier filing in this sequence is available for direct comparison.
  • Current net transaction value: $0.

Research use

  • This tells you what this filing adds before you inspect full transaction and derivative tables.
  • You can trace every row back to the original SEC filing document.

Evidence

Official SEC source

Ownership activity is grounded in SEC Form 3 disclosures.

View source filing

Reporting Owners (1)

CIK 0002091865 Primary reporting owner

Irish Simon

Relationship
Chief Executive Officer, Director
Address
2730 W. TYVOLA ROAD, SUITE 100, CHARLOTTE
Signature
/s/ Steven M. Millsap, pursuant to Power of Attorney
Signature date
07 Nov 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

IMSR holding

Common Stock, par value $0.0001 per share ("Common Stock")

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
2,295,934
Date
28 Oct 2025
Ownership
Direct
Footnotes
F1
IMSR holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
2,818,520
Date
28 Oct 2025
Ownership
Through LLC
Footnotes
F1
IMSR holding

Common Stock

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
52,255
Date
28 Oct 2025
Ownership
Through Defined Benefit Plan
Footnotes
F1

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
24,140
Exercise price
$2.01
Footnotes
F2
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
107,288
Exercise price
$2.24
Footnotes
F2
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
178,812
Exercise price
$0.2013
Footnotes
F2, F7
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
2,279,850
Exercise price
$0.2013
Footnotes
F2, F7
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
178,812
Exercise price
$0.2013
Footnotes
F2, F7
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
2,172,563
Exercise price
$0.2013
Footnotes
F2, F7
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
98,347
Exercise price
$2.24
Footnotes
F3
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
21,905
Exercise price
$2.24
Footnotes
F2
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
26,286
Exercise price
$2.24
Footnotes
F2
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
4,381
Exercise price
$2.24
Footnotes
F2
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
89,406
Exercise price
$2.24
Footnotes
F3
IMSR holding Derivative

Stock Option (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
178,812
Exercise price
$2.24
Footnotes
F3
IMSR holding Derivative

Restricted Stock Units

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
1,023,160
Exercise price
Footnotes
F4
IMSR holding Derivative

Warrants (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
44,703
Exercise price
$2.24
Footnotes
F5
IMSR holding Derivative

Warrants (Right to Buy)

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Through Defined Benefit Plan
Underlying class
Common Stock
Underlying amount
89,406
Exercise price
$2.24
Footnotes
F5
IMSR holding Derivative

Contingent Value Right

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Direct
Underlying class
Common Stock
Underlying amount
Exercise price
Footnotes
F6
IMSR holding Derivative

Contingent Value Right

No transaction description listed

Transaction value
Shares
Change %
Price
Shares after
Date
28 Oct 2025
Ownership
Through Defined Benefit Plan
Underlying class
Common Stock
Underlying amount
Exercise price
Footnotes
F6
* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 7 footnotes

Footnote F1

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.

Footnote F2

Consists of options granted pursuant to the Legacy Terrestrial Second Amended and Restated 2024 Stock Option Plan. The options are currently exercisable.

Footnote F3

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 and accelerated vesting in certain events.

Footnote F4

Each restricted stock unit represents a contingent right to acquire one share of Common Stock. The restricted stock units vest in one-half increments on each of the first and second anniversaries of the grant date, subject to Mr. Irish's continued employment through each applicable vesting date and accelerated vesting in certain events.

Footnote F5

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

Footnote F6

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).

Footnote F7

Price is expressed in Canadian dollars.

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