Deep Fission FISN Insider Ownership

NASDAQ FISN
$5.24 -0.18 (-3.23%)
At close: Sep 29, 2026 · 4:00 PM EDT

Insider Holdings by Owner

18.27Mn Shares

Insider Ownership Statistics

as of 30 Sep, 2026
Insider Ownership
33.16%
■0% pp QoQ
Shares Held by Insiders
18.27Mn
filed for Sep 2026
■0.00% QoQ
Shares Outstanding
55.10Mn
55,098,477 shares
Direct Holdings
13.21Mn
Indirect: 5.06Mn
Net Shares Traded (QoQ)
0
no net change in Sep 2026
Insiders Holding Shares
5
with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding
Latest —
Average ownership —
Peak ownership —

Shares Purchased/Sold by Insiders

Bought Sold
Latest quarter —
Net over range —
Buying quarters —

Insider Ownership Summary

Quarter ending 30 Sep, 2026

As of September 29, 2026, the three largest insider holders of FISN are Elizabeth Muller (President And Chief Executive, 10.25Mn shares), Richard Muller (Chief Technology Officer, 5.20Mn shares), Mark N. Tompkins (Other, 1.89Mn shares).

Form 4 Holdings

Insiders Holding FISN

Insiders 5
Shares held 18.27Mn
Of outstanding 33.16%
# Insider Position Direct Indirect Total Share of Insiders Last Filed
1 Elizabeth Muller Chief Executive Officer 5,745,877 5,057,855 10,803,732 59.1% 12 Dec, 2025
2 Richard Muller Chief Technology Officer 5,196,426 0 5,196,426 28.4% 09 Sep, 2025
3 Mark N. Tompkins Other 1,891,667 0 1,891,667 10.4% 08 Sep, 2025
4 Ian Seth Jacobs President, Ceo, Cfo, Secretary 275,000 0 275,000 1.5% 28 Aug, 2025
5 William Mark Schmitz Chief Financial Officer 103,928 0 103,928 0.6% 09 Sep, 2025

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

34 Insider Transactions

Source SEC Form 4
Latest quarter Sep 2026
Download Data
Date Insider Position Transaction Shares Price Value Shares Held After Ownership
23 Jul, 2026 Jonathon Angell Director Acquired A 16,973 $0.00 $0 16,973 Direct
23 Jul, 2026 Blake Janover Director Acquired A 18,962 $0.00 $0 18,962 Direct
23 Jul, 2026 Tepper Leslie Goldman Director Acquired A 19,204 $0.00 $0 19,204 Direct
23 Jul, 2026 Thomas S Glanville Director Acquired A 19,156 $0.00 $0 19,156 Direct
09 Mar, 2026 Tepper Leslie Goldman Director Acquired A 3,334 $0.00 $0 103,334 Direct
09 Mar, 2026 William Mark Schmitz Chief Financial Officer Acquired A 223,000 $0.00 $0 223,980 Direct
09 Mar, 2026 Mark Wayne Peres Chief Nuclear Officer Acquired A 223,000 $0.00 $0 263,000 Direct
09 Mar, 2026 Richard Muller Chief Technology Officer Acquired A 223,000 $0.00 $0 872,363 Direct
09 Mar, 2026 Jonathon Angell Director Acquired A 3,334 $0.00 $0 103,334 Direct
09 Mar, 2026 Michael Allen Brasel Chief Operating Officer Acquired A 445,000 $0.00 $0 530,000 Direct
09 Mar, 2026 Elizabeth Muller Chief Executive Officer Acquired A 2,600,000 $0.00 $0 4,150,300 Direct
09 Mar, 2026 Blake Janover Director Acquired A 3,334 $0.00 $0 103,334 Direct
09 Mar, 2026 Jonathan H Gordon General Counsel Acquired A 223,000 $0.00 $0 328,000 Direct
09 Mar, 2026 Thomas S Glanville Director Acquired A 3,334 $0.00 $0 103,334 Direct
18 Feb, 2026 Michael Allen Brasel Officer Acquired A 15,000 $0.00 $0 15,000 Direct
18 Feb, 2026 Jonathan H Gordon Officer Acquired A 20,000 $0.00 $0 20,000 Direct
18 Feb, 2026 William Mark Schmitz Chief Financial Officer Acquired A 15,000 $0.00 $0 15,000 Direct
19 Feb, 2026 Mark Wayne Peres Chief Nuclear Officer Acquired A 25,000 $0.00 $0 25,000 Direct
19 Feb, 2026 Mark Wayne Peres Chief Nuclear Officer Acquired A 15,000 $0.00 $0 15,000 Direct
07 Nov, 2025 Michael Allen Brasel Officer Acquired A 70,000 $0.00 $0 70,000 Direct