Roberto Marco Sella - 29 Oct 2025 SCHEDULE 13G Report for Terrestrial Energy Inc. Common Stock, par value $0.0001 per share (IMSR)

Filing manager: Roberto Marco Sella
Reporting owner: Roberto Marco Sella
Security: Terrestrial Energy Inc. Common Stock, par value $0.0001 per share
Beneficially owned shares: 15,378,689 shares
Large-stake signal: Form
SCHEDULE 13G
Passive or exempt beneficial ownership filing.
Ownership
14%
Beneficial ownership of this reported class.
Shares
15,378,689 shares
Shares beneficially owned as disclosed.
Event date
29 Oct 2025
Date tied to the ownership event or amendment.
Accepted by SEC
22 Jan 2026
EDGAR acceptance date.
How to read this large-stake filing
Schedule 13D/G filings focus on beneficial ownership stakes, not a full portfolio.
Compare this filing with the holder history and issuer page before treating the percentage as a current position.
Use amendments to understand whether the disclosed stake increased, decreased, or changed reporting status.
Class ownership: 14%
Symbol: IMSR
Shares outstanding: 107,243,298 shares
SEC form: SCHEDULE 13G
Accepted by SEC: 22 Jan 2026, 17:16:01 UTC
Event date: 29 Oct 2025
Source filing: View source filing

Key filing fact

Roberto Marco Sella disclosed 14% ownership in Terrestrial Energy Inc. Common Stock, par value $0.0001 per share (IMSR) on 29 Oct 2025.

Key facts

Roberto Marco Sella filed SCHEDULE 13G for Terrestrial Energy Inc. Common Stock, par value $0.0001 per share (IMSR).
Disclosed ownership: 14%.
Date of event: 29 Oct 2025.

This page turns one Schedule 13D/G filing into a quick large-stake read before the raw reporting-person rows.
Use the linked SEC filing as the source of truth for ownership percentages, shares, and reporting-party details.

Backed by Schedule 13D/13G

Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.

Reporting persons

Names, ownership percentages, voting power, signatures, titles, and CIKs as disclosed in this Schedule 13D/G filing.

Name	Ownership	Shares owned	Sole voting power	Shared voting power	Signature	Title
Roberto Marco Sella	14%	15,378,689	719,433	14,659,256	/s/ Roberto Sella	Roberto Sella
Roberto M. Sella 2012 Family Trust	1.4%	1,538,319	0	1,538,319	/s/ Roberto Sella	Roberto Sella, as Authorized Party
LL Charitable Foundation	0.62%	653,334	0	653,334	/s/ Roberto Sella	Roberto Sella, its President and Director

CIK / CUSIP context first

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