---
schema_version: "secwatch.filing_event.v1"
accession: "0001213900-25-093191"
form_type: "8-K"
ticker: "IMSR"
cik: "0002019804"
company_name: "Terrestrial Energy Inc. /DE/"
filed_at: "2025-09-29T23:59:59+00:00"
generated_at: "2026-05-17T05:27:59.202408+00:00"
event_type: "other_material"
sentiment: "positive"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# HCM II and Terrestrial Energy: SEC declares S-4 effective, shareholder meeting set for Oct 20

## Summary
- SEC declared effective the Registration Statement on Form S-4 on September 26, 2025 for the business combination.
- HCM II shareholders to vote at Extraordinary General Meeting on October 20, 2025; record date September 24, 2025.
- Post-combination company plans to list on Nasdaq under symbols IMSR and IMSRW upon closing.
- Terrestrial Energy develops IMSR small modular nuclear plants with Generation IV technology.
- Definitive proxy statement/prospectus began mailing to shareholders on September 26, 2025.

## SEC filing metadata
- accession: 0001213900-25-093191
- form_type: 8-K
- ticker: IMSR
- cik: 0002019804
- company_name: Terrestrial Energy Inc. /DE/
- filed_at: 2025-09-29T23:59:59+00:00
- event_type: other_material
- sentiment: positive
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01, 9.01, 7.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/2019804/000121390025093191/0001213900-25-093191-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/2019804/000121390025093191/ea0259069-8k425_hcm2acq.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001213900-25-093191
- JSON: https://secwatch.observer/filing/0001213900-25-093191.json
- Plain text: https://secwatch.observer/filing/0001213900-25-093191.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.