Latest Period
Q4 2025
- Info
- Insider Trading
- Financials
- Holders: IMSR, IMSRW
Security Snapshot
Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") (IMSR) Institutional Ownership
CUSIP: 881454102
13F Institutional Holders and Ownership History from Q4 2025 to Q1 2026
Institutions Reporting
82
Shares (Excl. Options)
21,415,986
Price
$6.11
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- Type / Class
- Equity / Common stock, par value $0.0001 per share (the "Shares")
- Symbol
- IMSR on Nasdaq
- Shares outstanding
- 104,718,000
- Price per share
- $6.00
- All holders as of 31 Dec 2025
- Q4 2025
- Total 13F shares
- 21,415,986
- Total reported value
- $130,661,482
- % of total 13F portfolios
- 0%
- Share change
- +21,387,486
- Value change
- +$130,487,347
- Number of holders
- 82
Reported Shares, Excluding Options vs Price
Reported Value, Excluding Options
Total Investors
Quick Takeaways
- IMSR - Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") is tracked under CUSIP 881454102.
- 82 institutions reported positions in Q4 2025.
- 6 significant owners is listed from Schedule 13D/13G reporting.
What Changed
- Holder count moved from 82 to 4 between Q4 2025 and Q1 2026.
- Reported value moved from $130,661,482 to $12,955,986.
Why This Matters
- You can quickly see who holds this security, then open quarter and manager detail pages for full evidence.
- 13F and Schedule 13D/13G sections are kept together so you can cross-check institutional and beneficial ownership context.
Source Evidence
Source: SEC Form 13F
Open SEC Evidence
Latest holder context comes from 82 institutions filings for Q4 2025.
Investment Quick Answers
What is CUSIP 881454102?
CUSIP 881454102 identifies IMSR - Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") in SEC 13F datasets.
Where can I see the latest institutional holders?
Review the Q4 2025 holders report and the ownership history table below.
Continue With The Right Next Step
- Latest 13F filings - identify new institutional portfolio moves.
- Latest Schedule 13D/13G reports - cross-check beneficial ownership events.
- All institutional ownership pages - compare nearby CUSIPs and holder concentration.
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 881454102:
Significant Owners of Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") (IMSR) based on Schedule 13D/G filings
| Filer | Ownership | Change % | Holdings Value | Net Change | Nb Shares | Change % | Reporting Name | Report Period |
|---|---|---|---|---|---|---|---|---|
| Sella Roberto Marco | 14% | $93,974,555 | 15,378,689 | Roberto Marco Sella | 29 Oct 2025 | |||
| Irish Simon | 13% | 13,586,445 | Simon Irish | 28 Oct 2025 | ||||
| LeBlanc David Michael | 9.7% | 11,400,410 | David LeBlanc | 28 Oct 2025 | ||||
| CITADEL ADVISORS LLC | 2.2% | $24,811,883 | 2,303,796 | Kenneth Griffin | 31 Dec 2025 | |||
| Linden Capital L.P. | 0.9% | 209,426 | Linden Capital L.P. | 30 Sep 2025 | ||||
| Magnetar Financial LLC | 0.62% | 142,304 | MAGNETAR FINANCIAL LLC | 30 Sep 2025 |
As of 31 Dec 2025, 82 institutional investors reported holding 21,415,986 shares of Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") (IMSR). This represents 20% of the company’s total 104,718,000 outstanding shares.
Top 25 Institutional Shareholders
The largest institutional shareholders of Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") (IMSR) together control 18% of the company’s outstanding shares — a level of ownership often associated with strong institutional conviction and long‑term capital commitment.
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| CITADEL ADVISORS LLC | 1.9% | 2,029,208 | 0.01% | $12,398,461 | |
| VANGUARD GROUP INC | 1.8% | 1,849,446 | 0% | $11,300,115 | |
| Balyasny Asset Management L.P. | 1.3% | 1,400,953 | 0.02% | $8,559,823 | |
| JPMORGAN CHASE & CO | 1.1% | 1,170,087 | 0% | $7,149,232 | |
| BlackRock, Inc. | 1% | 1,092,501 | 0% | $6,675,182 | |
| D. E. Shaw & Co., Inc. | 1% | 1,079,546 | 0.01% | $6,596,026 | |
| Senator Investment Group LP | 0.86% | 900,000 | 0.22% | $5,499,000 | |
| GEODE CAPITAL MANAGEMENT, LLC | 0.76% | 796,327 | 0% | $4,868,025 | |
| Verition Fund Management LLC | 0.72% | 753,803 | 0.02% | $4,605,736 | |
| MMCAP International Inc. SPC | 0.72% | 750,000 | 0.46% | $4,582,500 | |
| Hudson Bay Capital Management LP | 0.7% | 736,038 | 0.03% | $4,497,192 | |
| Alyeska Investment Group, L.P. | 0.69% | 722,000 | 0.01% | $4,383,914 | |
| WINTON GROUP Ltd | 0.62% | 646,190 | 0.14% | $3,948,221 | |
| LMR Partners LLP | 0.56% | 588,214 | 0.03% | $3,593,988 | |
| CANTOR FITZGERALD, L. P. | 0.53% | 550,000 | 0.1% | $3,360,500 | |
| UBS Group AG | 0.49% | 512,644 | 0% | $3,132,255 | |
| Galaxy Group Investments LLC | 0.48% | 500,000 | 0.42% | $3,055,000 | |
| HBK INVESTMENTS L P | 0.48% | 500,000 | 0.03% | $3,055,000 | |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 0.39% | 410,877 | 0% | $2,510,458 | |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 0.33% | 348,532 | 0% | $2,129,531 | |
| STATE STREET CORP | 0.31% | 326,700 | 0% | $1,996,137 | |
| JANE STREET GROUP, LLC | 0.29% | 301,213 | 0% | $1,840,411 | |
| GOLDMAN SACHS GROUP INC | 0.27% | 281,764 | 0% | $1,721,578 | |
| Shay Capital LLC | 0.26% | 277,363 | 0.27% | $1,694,688 | |
| HIGHBRIDGE CAPITAL MANAGEMENT LLC | 0.23% | 244,000 | 0.07% | $1,490,840 |