Dassault Systèmes Tumbles as AI Fears Hit Growth Story - Moby THE GIST Dassault Systèmes shares plunged about 20%, their worst day on record, after weak fourth-quarter results and a soft 2026 outlook. In a market obsessed with AI winners and losers, the French industrial software group suddenly looks exposed. WHAT HAPPENED Dassault reported fourth quarter revenue of €1.68 billion (about $2 billion), down 4% year on year and below expectations of around €1.74 billion to €1.75 billion. At constant currenci ...