Seoul shares plunged nearly 9 percent on Monday as investors sold technology stocks amid renewed Middle East tensions. The benchmark KOSPI fell 669.01 points to close at 6,806.93.
The KOSPI opened 0.85 percent lower before extending losses and triggering a circuit breaker that halted trading for 20 minutes. It was the seventh activation of the measure this year.
Institutions and foreigners sold a net 2.22 trillion won and 1.7 trillion won worth of shares respectively, while individuals bought a net 3.9 trillion won. Samsung Electronics fell 10.7 percent to 254,500 won, and SK hynix dropped 15.37 percent to 1,845,000 won.
Investor sentiment was dampened by uncertainty in the Middle East after the United States and Iran exchanged fresh strikes over the status of the Strait of Hormuz. Samsung Securities noted that newly introduced single-stock leveraged ETFs linked to Samsung Electronics and SK hynix fueled volatility.