South Korean stocks fell sharply on September 11 as escalating U.S.-Iran tensions drove oil prices higher and pushed the U.S. 30-year Treasury yield above 5%, reviving inflation and interest-rate concerns. The benchmark Korea Composite Stock Price Index opened down 3.29% and briefly approached 6,800 before recovering some ground to close at 6,909.91, down 124.01 points, or 1.76%. Foreign and institutional investors were net sellers of 2.4225 trillion won and 1.6476 trillion won, respectively, while individuals and other corporate investors bought a combined 4.0712 trillion won. Samsung Electronics fell 3.53% and SK Hynix declined 2.21%. Security, quantum-cryptography and multilayer ceramic capacitor stocks rose against the broader market trend. The Kosdaq also fell nearly 2% to around 820. The decline followed losses on Wall Street, where the Dow Jones Industrial Average, S&P 500 and Nasdaq Composite fell 0.60%, 0.58% and 0.65%, respectively. Trading volume on the KOSPI was moderate at 265.92 million shares worth 19.39 trillion won, while the Korean won weakened against the U.S. dollar.