CAC 40 falls amid US-Iran tensions and market volatility

The French stock market experienced significant volatility on August 31, 2026. The CAC 40 index fell 0.79% to 8,334 points, marking a 2% decline for the month of August—the largest monthly drop since March. This downturn was driven by heightened geopolitical tensions between the United States and Iran following military strikes, which pushed Brent crude oil prices toward $91 per barrel.

Individual stock performances varied widely. Soitec saw a surge of over 6% due to rising demand for artificial intelligence infrastructure, while Advicenne dropped 36% following the withdrawal of a drug authorization request in the United States. In terms of trading volume, Bollore recorded an abnormal increase of 2,858% compared to its five-day average, and Nexity saw 3.00% of its capital change hands.

Economic concerns also persist regarding potential interest rate hikes in the United States. Following recent central bank commentary, markets have increased the probability of a rate hike in September to approximately 60%. Additionally, Airbus is reportedly considering divesting its U.S. space activities to strengthen its European space operations.