DEEP FISSION INC FISN
COM · Common Stock · CUSIP 243927100
- SectorUtilities
- IndustryElectric Services
- HeadquartersBerkeley, CA
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once. Holder counts are more reliable. Shares outstanding: 58.9m as of 2026-07-27, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $11.04.
Biggest buyers
| Blue Owl Capital Holdings LP | New | +1.3m |
| Elevation Wealth Management LLC | New | +298.3k |
| UBS Group AG | New | +198.5k |
| CONSOLIDATED PRESS INTERNATIONAL HOLDINGS LTD | New | +133.3k |
| CITADEL ADVISORS LLC | New | +110.0k |
| LPL Financial LLC | New | +70.9k |
| GEODE CAPITAL MANAGEMENT, LLC | New | +27.3k |
| Essential Investment Partners LLC | New | +26.4k |
| CHAPIN DAVIS, INC. | New | +19.0k |
| GOLDMAN SACHS GROUP INC | New | +17.4k |
Biggest sellers
| None |
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
Muller Elizabeth
13D · may seek influence
new · filed 2025-09-23
Stated purposeThe Reporting Person acquired the Common Stock in connection with the Merger. The information contained in Item 3 of this Schedule 13D is incorporated herein by reference. The Reporting Person serves as a Director and President and Chief Executive Officer of the Issuer. Accordingly, the Reporting Person may have influence over the corporate activities of the Issuer, including activities that may relate to items described in clauses (a) through (j) of Item 4 of this Schedule 13D. Subject to the Registration Rights Agreement described in Item 6 of this Schedule 13D, the Reporting Person may, from time to time, purchase or sell securities of the Issuer as appropriate for her personal circumstances. Except as described in this Schedule 13D, the Reporting Person does not have any present plans… Full filing |
20.6% |
Muller Richard
13D · may seek influence
new · filed 2025-09-23
Stated purposeThe Reporting Person acquired the Common Stock in connection with the Merger. The information contained in Item 3 of this Schedule 13D is incorporated herein by reference. The Reporting Person serves as a Director and Chief Technology Officer of the Issuer. Accordingly, the Reporting Person may have influence over the corporate activities of the Issuer, including activities that may relate to items described in clauses (a) through (j) of Item 4 of this Schedule 13D. Subject to the Registration Rights Agreement described in Item 6 of this Schedule 13D, the Reporting Person may, from time to time, purchase or sell securities of the Issuer as appropriate for his personal circumstances. Except as described in this Schedule 13D, the Reporting Person does not have any present plans or proposals… Full filing |
10.6% |
| Tompkins Mark N. 13G · passive investor -0.2 pts · filed 2026-05-15 | 5.6% |
| EE Holdings Ltd 13G · exempt (held before listing) new · filed 2025-11-03 | 5.5% |
Insider purchases and sales since 1 Apr 2026
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 0 | — | — |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 1 | — | 1 | — | — |
| Q4 2025 | 0 | — | 0 | — | — |
| Q1 2026 | 0 | — | 0 | — | — |
| Q2 2026 | 0 | — | 0 | — | — |
| Q3 2026 | 0 | — | 0 | — | — |
None reported since 1 Apr 2026.
Holders, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| Blue Owl Capital Holdings LP 2.24% of their portfolio | 1.3m $14.7m | New |
| Elevation Wealth Management LLC 2.47% of their portfolio | 298.3k $3.3m | New |
| UBS Group AG 0.00% of their portfolio | 198.5k $2.2m | New |
| CONSOLIDATED PRESS INTERNATIONAL HOLDINGS LTD 56.42% of their portfolio | 133.3k $1.5m | New |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 110.0k $1.2m | New |
| LPL Financial LLC 0.00% of their portfolio | 70.9k $782.3k | New |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 27.3k $301.8k | New |
| Essential Investment Partners LLC 0.23% of their portfolio | 26.4k $291.5k | New |
| CHAPIN DAVIS, INC. 0.04% of their portfolio | 19.0k $209.8k | New |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 17.4k $191.8k | New |
| BHK Investment Advisors, LLC 0.05% of their portfolio | 15.0k $165.6k | New |
| PRELUDE CAPITAL MANAGEMENT, LLC 0.01% of their portfolio | 14.7k $162.4k | New |
| TRAPHAGEN INVESTMENT ADVISORS LLC 0.01% of their portfolio | 13.7k $150.9k | New |
| Integrated Wealth Concepts LLC 0.00% of their portfolio | 9.6k $106.0k | New |
| MORGAN STANLEY 0.00% of their portfolio | 6.0k $66.8k | New |
| US BANCORP \DE\ 0.00% of their portfolio | 1.1k $12.1k | New |
| Clearstead Advisors, LLC 0.00% of their portfolio | 500 $5.5k | New |
| FNY Investment Advisers, LLC 0.00% of their portfolio | 500 $5.0k | New |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 335 $3.7k | New |
| JONES FINANCIAL COMPANIES LLLP 0.00% of their portfolio | 300 $3.2k | New |
| NATIONAL BANK OF CANADA /FI/ 0.00% of their portfolio | 200 $2.2k | New |
| CITIGROUP INC 0.00% of their portfolio | 2 $22 | New |
| Keating Financial Advisory Services, Inc. 0.00% of their portfolio | 0 $0 | New |