A financial data screen at Hana Bank's dealing room in central Seoul shows the benchmark Kospi at 7,477.46, shortly after the opening bell on Monday. (Yonhap) The South Korean benchmark Kospi plunged more than 8 percent Monday, mirroring a rout in US semiconductor stocks on Wall Street, which triggered a circuit breaker.The Kospi opened 1.38 percent lower at 8,048.09. Soon after the opening bell, selling accelerated, pushing the index below the 8,000 mark. It stood at 7,477.46, down 8.37 percent, as of 9:12 a.m.A circuit breaker was triggered, halting program trading for 20 minutes after the benchmark index plunged more than 8 percent.Foreign investors were net sellers of 352.7 billion won ($227.3 million) worth of shares, while retail and institutional investors purchased a net 247.5 billion won and 112.8 billion won, respectively.Semiconductor stocks paced the decline, with Samsung Electronics slumping 9.27 percent to 298,500 won. SK hynix fell 8.02 percent to 1.9 million won, slipping below the 2 million won threshold.Chip stocks led the plunge with Samsung Electronics shedding 9.27 percdent to 298,500 won. SK hynix dipped 8.02 percent to 1.9 million, sliding below the 2 million won mark.SK Square tumbled 11.13 percent to 1.11 million won, while Hyundai Motor dropped 9.86 percent to 631,000 won.All three major US stock indexes ended the session sharply lower Friday, with plunging chip stocks dragging the tech-heavy Nasdaq Composite down 4.18 percent.The S&P 500 fell 2.64 percent, snapping its nine-week streak of Friday-to-Friday gains.