Latest Period
Q2 2026
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 Q2 2026
Institutions Reporting
106
Shares (Excl. Options)
21,258,990
Price
$7.08
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- Security type / class
- Equity / Common stock, par value $0.0001 per share (the "Shares")
- Symbol
- IMSR on Nasdaq
- All holders as of 30 Jun 2026
- Q2 2026
- Total 13F shares
- 21,258,990
- Total 13F value
- $150,290,025
- Portfolio coverage rank
- 0%
- Share change
- +2,912,016
- Value change
- +$21,215,947
- Number of holders
- 106
- Shares outstanding
- 104,718,000
- SEC-reported price per share
- $5.22
Latest holder snapshot
5 signals
Issuer context
Names, identifiers, and filing context for this profile.
2 identity fields
13F Shares, Excluding Options vs Price
13F Value, Excluding Options
Total Investors
Key facts
- IMSR - Terrestrial Energy Inc. /DE/ - Common stock, par value $0.0001 per share (the "Shares") is tracked under CUSIP 881454102.
- 106 institutions reported positions in Q2 2026.
- 6 significant owners is listed from Schedule 13D/13G reporting.
Change
- Holder count moved from 88 to 106 between Q1 2026 and Q2 2026.
- SEC-reported value moved from $111,253,410 to $150,290,025.
Research use
- 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.
Evidence
Source: SEC Form 13F
Open SEC evidence
Latest holder context comes from 106 institutions filings for Q2 2026.
Security key
881454102
Latest holder period
Q2 2026
13F holders
106
13D/G owners
6
CIK / CUSIP context first
Open Q2 2026 holders
IMSR full holder history
Terrestrial Energy Inc. /DE/ SEC filings
Terrestrial Energy Inc. /DE/ company facts
Terrestrial Energy Inc. /DE/ insider transactions
Broader feeds
Recent Quarterly Holder Reports
Open recent reporting periods for CUSIP 881454102:
13D/G owners
Significant owners
Large-stake holder rows connected to Schedule 13D/G evidence.
Rows
6
Security
IMSR
| 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 30 Jun 2026, 106 institutional investors reported holding 21,258,990 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.
13F concentration
Top 25 institutional shareholders
Largest 13F positions for this security by reported shares and value.
Top holder share
17%
| Institution | Ownership % | Shares Held | Share Change % | Portfolio % | Holdings Value |
|---|---|---|---|---|---|
| VANGUARD CAPITAL MANAGEMENT LLC | 3.3% | 3,414,196 | +162% | 0% | $24,172,508 |
| EXCHANGE TRADED CONCEPTS, LLC | 2.1% | 2,160,074 | +3.3% | 0.08% | $15,293,324 |
| UBS Group AG | 1.7% | 1,772,173 | +259% | 0% | $12,546,985 |
| HRT FINANCIAL LP | 1.1% | 1,125,849 | 0.01% | $7,971,000 | |
| BlackRock, Inc. | 1% | 1,074,524 | -4.1% | 0% | $7,607,630 |
| JPMORGAN CHASE & CO | 0.92% | 966,797 | -9.9% | 0% | $6,777,247 |
| GEODE CAPITAL MANAGEMENT, LLC | 0.66% | 693,934 | +5.2% | 0% | $4,915,460 |
| LMR Partners LLP | 0.66% | 690,702 | 0% | 0.04% | $4,890,170 |
| D. E. Shaw & Co., Inc. | 0.64% | 667,968 | -45% | 0% | $4,729,214 |
| Hudson Bay Capital Management LP | 0.56% | 589,293 | +30% | 0.02% | $4,172,195 |
| Pacer Advisors, Inc. | 0.55% | 574,618 | 0.01% | $4,068,000 | |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | 0.55% | 571,832 | +73% | 0% | $4,048,571 |
| WINTON GROUP Ltd | 0.48% | 504,000 | +1.6% | 0.12% | $3,568,320 |
| MORGAN STANLEY | 0.39% | 412,815 | +45% | 0% | $2,922,730 |
| Verition Fund Management LLC | 0.36% | 374,958 | -16% | 0.02% | $2,654,703 |
| VANGUARD FIDUCIARY TRUST CO | 0.35% | 365,772 | +22% | 0% | $2,589,666 |
| Vennlight Capital Management, LP | 0.34% | 353,010 | -39% | 1.7% | $2,499,311 |
| STATE STREET CORP | 0.33% | 346,696 | +0.34% | 0% | $2,454,608 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC | 0.32% | 333,599 | -1.3% | 0% | $2,361,881 |
| HIGHBRIDGE CAPITAL MANAGEMENT LLC | 0.23% | 244,000 | 0.06% | $1,710,440 | |
| JANE STREET GROUP, LLC | 0.23% | 240,719 | 0% | $1,704,290 | |
| Alyeska Investment Group, L.P. | 0.21% | 222,000 | -69% | 0% | $1,571,760 |
| RENAISSANCE TECHNOLOGIES LLC | 0.18% | 183,800 | -55% | 0% | $1,301,304 |
| Creek Drive Management Group LLC | 0.17% | 175,000 | -47% | 0.77% | $1,239,000 |
| CastleKnight Management LP | 0.16% | 165,400 | +172% | 0.04% | $1,171,032 |
Quarter history
Institutional holders across reporting periods
Holder count, reported shares/value, and median price by quarter.
Periods
3
Latest
Q2 2026
Rows shown
1-3 of 3