European Markets Slide Amid Escalating Iran Tensions; Rheinmetall Shares Drop 18%

European stock markets opened lower on March 11, 2026, as renewed fears of military escalation involving Iran sent shockwaves through investor sentiment. The STOXX Europe 600 index fell 1.9%, erasing gains from the prior session, amid reports of intensified missile activity near the Strait of Hormuz and increased Iranian military deployments in the region. The defense sector bore the brunt of the sell-off, with Rheinmetall AG (RHM.DE) shedding 18.1% in early trading, its steepest one-day drop in over 18 months. The sell-off extended into energy markets, where crude oil prices rose 3.2% to $87.60 per barrel (CL=F), reflecting supply disruption concerns. The spike in oil prices was mirrored by a jump in the CBOE Volatility Index (VIX), which climbed to 28.7, up 22% from the prior session, indicating a sharp increase in perceived market risk. Investors began unwinding positions in cyclical and high-beta sectors, particularly those sensitive to geopolitical risk, including defense and energy firms. The broader implications point to a shift in market dynamics, with safe-haven assets gaining traction. The decline in European equities contrasts with modest gains in German bunds and U.S. Treasury yields, suggesting a flight-to-safety move. Rheinmetall’s sharp drop underscores how geopolitical risk can rapidly alter the valuation of defense stocks, even those with strong long-term contracts and global exposure. The company’s market cap lost over €4.2 billion in a single day. Market participants now await further updates from diplomatic channels, with analysts warning that any military confrontation involving Iran could trigger a sustained spike in oil prices and continued volatility across global equity and commodity markets.