Core Viewpoint - The decline in Sanofi's stock on February 12, 2026, is primarily attributed to sudden management changes and market concerns regarding its research and development prospects [1] Group 1: Executive Changes - On February 12, the company announced that CEO Paul Hudson would step down, with Merck executive Belén Garijo set to take over in April. This unexpected change was interpreted by the market as a sign of the board's impatience due to the lack of expected results from R&D investments. The stock closed down 4.51% at $47.03, with an intraday low of $46.71 [2] Group 2: Company Fundamentals - Despite a 7% year-over-year revenue growth in Q4 2025 (13.3% growth at constant exchange rates), investors are more concerned about the risks associated with a weak R&D pipeline. In the past 12 months, the experimental multiple sclerosis drug tolebrutinib failed in key trials, and the clinical trial data for the atopic dermatitis candidate amlitelimab has been mixed. Jefferies reported that the management change may indicate slow progress in R&D transformation [3][4] Group 3: Performance and Operations - Dupixent accounts for over 30% of the company's revenue, but its patent is set to expire in the early 2030s, and Sanofi has not clearly identified new drugs to replace its revenue scale. Analysts from AlphaValue noted that investors have lost patience with repeated R&D failures, and the leadership change has intensified short-term uncertainty [4] Group 4: Industry Policy and Environment - The vaccine business contributes nearly 20% to revenue, but sales in Q4 declined by 2.5% year-over-year. The company expects this business to continue declining in 2026, with negative impacts from the U.S. policy environment on vaccine promotion. Additionally, the broader market decline, with the Nasdaq index falling by 2.03%, exacerbated the stock's drop [5]