---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-26-019327"
form_type: "8-K"
ticker: "FISN"
cik: "0001918102"
company_name: "DEEP FISSION, INC."
filed_at: "2026-02-25T23:59:59+00:00"
generated_at: "2026-05-16T00:28:49.814075+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# Deep Fission appoints Chief Nuclear Officer; CEO receives $380K bonus

## Summary
- Mark Pérès appointed Chief Nuclear Officer effective Feb 19, 2026; base salary $300,000, target bonus 30%, 25,000 RSUs with service- and liquidity-based vesting.
- CEO Elizabeth Muller's target bonus raised from 50% to 100% of base salary for FY2026; one-time cash bonus of $380,000 paid in January 2026.
- CFO Mark Schmitz base salary increased from $250,000 to $300,000 effective Feb 1, 2026; bonus target unchanged at 30%.
- Pérès previously VP of Engineering at Deep Fission since Oct 2024; prior VP of Engineering at Kairos Power and Executive Project Director at Fluor.

## SEC filing metadata
- accession: 0001104659-26-019327
- form_type: 8-K
- ticker: FISN
- cik: 0001918102
- company_name: DEEP FISSION, INC.
- filed_at: 2026-02-25T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 5.02
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1918102/000110465926019327/0001104659-26-019327-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1918102/000110465926019327/tm267068d1_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-26-019327
- JSON: https://secwatch.observer/filing/0001104659-26-019327.json
- Plain text: https://secwatch.observer/filing/0001104659-26-019327.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.