Mistral AI is the only top-10 European unicorn on this calculator. Founded in Paris in 2023, it raised €640M in June 2024 at a €6.2B post-money valuation. Most of its 200-person team is French — and they hold BSPCEs, not ISOs or NSOs.
What's a BSPCE
BSPCE stands for Bon de Souscription de Parts de Créateur d'Entreprise — a stock option specific to French startups. Functionally identical to an ISO: you get the right to buy shares at a strike price set at grant. The difference is tax treatment under the French Code Général des Impôts.
BSPCE tax math
- If you exercise and sell after holding at least 2 years post-exercise: 30% flat tax (12.8% income tax + 17.2% social contributions).
- If you sell within 2 years: 47.2% flat tax (30% income tax + 17.2% social).
- No equivalent of US AMT — the strike-vs-fair-value spread is not taxed until sale.
Applied to Mistral
A typical 2023-cohort engineer at Mistral might hold 10,000 BSPCEs at €2 strike. Today's fair value (€41/share) means each share carries €39 of pre-tax spread. Holding for 2+ years post-exercise: €390K spread × (1 − 0.30) = €273K net. Selling within 2 years: €206K net. The 2-year hold is worth €67K to a typical employee.
BSPCEs are one of the best startup equity structures in the world from a tax perspective. If you're at a French startup considering an offer with BSPCE versus an equivalent US ISO/NSO mix, the BSPCE is usually better — assuming you trust the company's growth.