Key facts
- This page summarizes Roberto Marco Sella's Form 3/A - Amendment filing for Terrestrial Energy Inc. /DE/ (IMSR).
- 0 reported transactions and 4 derivative rows are listed below.
- Accepted by SEC: 17 Feb 2026, 21:00.
Roberto Marco Sella - 29 Oct 2025 Form 3/A - Amendment Insider Report for Terrestrial Energy Inc. /DE/ (IMSR)
- Reporting relationship
- 10%+ Owner
- Issuer ticker
- IMSR
- Reported as of
- 29 Oct 2025
- Net transaction value
- $0
- SEC form
- 3/A - Amendment
- Accepted by SEC
- 17 Feb 2026, 21:00:14 UTC
- Original report date
- 22 Jan 2026
- Prior SEC filing
- 02 Oct 2025
- Source filing
- View source filing
- Reporting owner signature
- /s/ Grant Levine, attorney-in-fact
Source evidence
Original filing metadata and source links for verification.
5 source fields
Reporting owner
1 detail
Key filing fact
Roberto Marco Sella filed Form 3/A - Amendment for Terrestrial Energy Inc. /DE/ (IMSR) on 17 Feb 2026.
Change
- Previous filing in this sequence was filed on 02 Oct 2025.
- 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
View source filing
Ownership activity is grounded in SEC Form 3/A - Amendment disclosures.
Reporting Owners (1)
CIK 0001770593
Primary reporting owner
Sella Roberto Marco
- Relationship
- 10%+ Owner
- Address
- C/O LL FUNDS, LLC, 2400 MARKET STREET, PHILADELPHIA
- Signature
- /s/ Grant Levine, attorney-in-fact
- Signature date
- 17 Feb 2026
Reported non-derivative transactions
Shares, units, or other non-derivative securities reported in this filing.
IMSR
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 180,316
- Date
- 29 Oct 2025
- Ownership
- Direct
- Footnotes
- F1
IMSR
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 12,244,088
- Date
- 29 Oct 2025
- Ownership
- See footnote
- Footnotes
- F1, F2
IMSR
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 807,873
- Date
- 29 Oct 2025
- Ownership
- See footnote
- Footnotes
- F1, F3
IMSR
holding
Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- 653,334
- Date
- 29 Oct 2025
- Ownership
- See footnote
- Footnotes
- F1, F4
Reported derivative securities
Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.
IMSR
holding
Derivative
Warrants to purchase shares of Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 29 Oct 2025
- Ownership
- Direct
- Underlying class
- Common Stock
- Underlying amount
- 539,117
- Exercise price
- $2.24
- Footnotes
- F1
IMSR
holding
Derivative
Warrants to purchase shares of Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 29 Oct 2025
- Ownership
- See footnote
- Underlying class
- Common Stock
- Underlying amount
- 223,515
- Exercise price
- $2.24
- Footnotes
- F1, F2, F5
IMSR
holding
Derivative
Warrants to purchase shares of Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 29 Oct 2025
- Ownership
- See footnote
- Underlying class
- Common Stock
- Underlying amount
- 59,902
- Exercise price
- $2.24
- Footnotes
- F1, F3, F5
IMSR
holding
Derivative
Warrants to purchase shares of Common Stock
No transaction description listed
- Transaction value
- Shares
- Change %
- Price
- Shares after
- Date
- 29 Oct 2025
- Ownership
- See footnote
- Underlying class
- Common Stock
- Underlying amount
- 670,544
- Exercise price
- $2.24
- Footnotes
- F1, F3, F5
* marks a reported price that did not pass the local price check.
Additional SEC filing notes
Filing notes and footnotes
Explanation of responses 5 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 persons 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
Represents securities jointly held by the reporting person and the reporting person's spouse. The reporting person disclaims beneficial ownership of the securities held jointly with his spouse except to the extent of his pecuniary interest therein
Footnote F3
Represents securities held by Roberto M. Sella 2012 Family Trust (the "Trust"), of which the reporting person is the trustee. The reporting person may be deemed to have voting and dispositive power over the shares held by the Trust. The reporting person disclaims beneficial ownership of the securities held by the Trust except to the extent of his pecuniary interest therein.
Footnote F4
Represents securities held by LL Charitable Foundation (the "Foundation"), of which the reporting person is the president. The reporting person may be deemed to have voting and dispositive power over the shares held by the Foundation. The reporting person disclaims beneficial ownership of the securities held by the Foundation except to the extent of his pecuniary interest therein.
Footnote F5
Amendment made solely to correct the footnote designations in Table II, Item 6.
SEC remarks
Exhibits List 24 - Confirming Statement