DEEP FISSION, INC. (FISN) IPO - S-1 Filing, Stock & Insider Activity
DEEP FISSION, INC. IPO - Status & S-1 Filing
- Ticker: FISN
- Status: Registered - S-1 filed with the SEC
- S-1 filed: 2025-12-01
- Exchange: NASDAQ
- Expected price range: $3.92–$2.90
- Shares offered: 5,333,333
- SEC CIK: 0001918102 · View the S-1 on SEC EDGAR →
Track every registration update on the InsiderAlpha IPO tracker.
Last SEC filing
DEEP FISSION, INC. (FISN) has filed 4 SEC Form 4 insider transactions in the last 90 days, with the most recent on 2026-07-27. 3 Form 8-K material event filings were reported by FISN in the last 90 days. InsiderAlpha tracks every FISN SEC filing - Form 4, Form 144, and 8-K - in real time, including Rule 10b5-1 plan detection.
About DEEP FISSION, INC. (FISN)
DEEP FISSION, INC. trades under the ticker FISN. InsiderAlpha tracks 26 primary SEC Form 4 filings from 12 reporting insiders for FISN since 2025, sourced directly from SEC EDGAR.
| Sector | Utilities insider trading |
|---|---|
| SIC classification | Electric Services (SIC 4911) |
| SEC CIK | 0001918102 |
90-Day SEC Filing Activity
| Form 4 filings (90d) | 4 |
|---|---|
| Form 8-K filings (90d) | 3 |
| Latest Form 4 filing | 2026-07-27 |
Recent FISN Insider Transactions (Form 4)
| Date | Insider | Role | Transaction | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|---|
| William Mark Schmitz | Chief Financial Officer | A - Grant or award | 103.9K | - | - | SEC | |
| Mark N. Tompkins | Insider | J - Other acquisition / disposition | 2.83M | $0.00 | - | SEC | |
| Elizabeth Muller | President and Chief Executive | A - Grant or award | 5.06M | - | - | SEC | |
| Richard Muller | Chief Technology Officer | A - Grant or award | 5.20M | - | - | SEC | |
| Elizabeth Muller | President and Chief Executive | A - Grant or award | 5.20M | - | - | SEC | |
| Ian Seth Jacobs | President, CEO, CFO, Secretary | P - Open-market purchase | 25.0K | $0.00 | $2 | SEC | |
| Mark N. Tompkins | Director | S - Open-market sale | 25.0K | $0.00 | $2 | SEC |
All transactions sourced from SEC EDGAR Form 4 filings for DEEP FISSION, INC. (FISN). Updated in real time as new filings are submitted to the SEC.
Most-Active FISN Insiders - Last 90 Days
| Insider | Form 4 filings | Total transaction value |
|---|---|---|
| Thomas S. Glanville | 1 | - |
| Tepper Leslie Goldman | 1 | - |
| Jonathon Angell | 1 | - |
| Blake Janover | 1 | - |
Recent FISN Form 8-K Material Events
- - Item 8.01, 9.01 [SEC]
- - Item 5.02, 5.07, 9.01 [SEC]
- - Item 8.01 [SEC]
- - Item 7.01, 9.01 · Financing · positive [SEC]
Deep Fission, Inc. announced on April 22, 2026 that it has confidentially submitted a draft S-1 registration statement with the SEC for a proposed public offering of common stock. This marks a significant milestone for the emerging growth company as it moves toward accessing publ - - Item 4.02 · Earnings · negative [SEC]
Deep Fission's Board concluded that previously issued financial statements for Q2 2025, full year 2024, and Q3 2025 should no longer be relied upon due to errors in valuations of SAFEs (Simple Agreements for Future Equity) and stock-based compensation. The company is currently ev
Recent Insider Filings
- - Thomas S. Glanville (Director)
- - Blake Janover (Director)
- - Tepper Leslie Goldman (Director)
- - Jonathon Angell (Director)
- - William Mark Schmitz (Chief Financial Officer)
Form 4 Transaction Code Reference
SEC Form 4 transactions are reported with a one-letter code indicating the type of transaction. Common codes you'll see in FISN insider filings:
| P | Open-market purchase by the insider |
|---|---|
| S | Open-market sale by the insider |
| A | Grant, award, or other acquisition from the issuer |
| M | Exercise or conversion of derivative security (e.g. options) |
| F | Payment of exercise price or tax liability via share withholding |
| G | Bona-fide gift of securities |
| D | Disposition to the issuer (e.g. share buyback participation) |
| J | Other acquisition or disposition |
| X | Exercise of in-the-money or at-the-money derivative security |
| C | Conversion of derivative security |
| V | Transaction voluntarily reported earlier than required |
FISN Insider Trading - FAQ
- What is the latest insider trade for FISN?
- DEEP FISSION, INC. (FISN) had 4 insider filings in the last 90 days, with the most recent on 2026-07-27. InsiderAlpha tracks every Form 4, Form 144, and 8-K filing in real time.
- How many insiders are buying FISN stock?
- 0 insider purchases of FISN were filed in the last 90 days.
- How many insiders are selling FISN stock?
- 0 insider sales of FISN were filed in the last 90 days.
- Where can I see FISN SEC filings (Form 4, 10-K, 10-Q, 8-K)?
- This page tracks FISN Form 4 insider transactions, Form 144 sale notices, and 8-K material event disclosures in one timeline. Annual 10-K and quarterly 10-Q reports live on the company's SEC EDGAR page.
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Learn More
- What is SEC Form 4?
- How to read insider buying signals
- Rule 10b5-1 trading plans explained
- The cluster buying signal
Open the live FISN dashboard on InsiderAlpha for real-time alerts, charting, and full historical filing search.