South Korea's benchmark KOSPI index triggered a circuit breaker on Thursday, halting trading for 20 minutes after the index plunged more than 8 percent in a tech-led selloff driven by doubts over the artificial intelligence investment boom and hotter-than-expected U.S. inflation data.
The Korea Exchange activated the trading halt at 12:38 p.m. local time, marking the ninth circuit breaker this year, according to Yonhap News Agency. By 11:20 a.m. the index had dropped 404 points, or 6.7 percent, to around 5,605, and losses later deepened past the 8 percent threshold that triggers a full-day suspension.
Chip giants Samsung Electronics and SK hynix led the decline, tumbling 7.9 percent and 9.9 percent respectively, Yonhap reported. CNA said both shares sank more than 10 percent at the session low. The rout tracked overnight losses on Wall Street, where the tech-heavy Nasdaq dropped nearly 2 percent after U.S. consumer price data came in above forecasts.
The U.S. Consumer Price Index for September rose 0.6 percent from August, the fastest monthly pace since April, Yonhap said, citing official data released Wednesday. CNA reported the year-over-year rate hit 3.7 percent, a five-month high, driven largely by a surge in energy costs after Iran effectively closed the Strait of Hormuz to crude shipments. Gasoline costs jumped 9.1 percent in September, accounting for more than half the monthly CPI increase.
Investors sold semiconductor shares on skepticism about the sustainability of AI spending, Yonhap said. The selling spread across Asia, with Tokyo's Nikkei 225 shedding more than 5 percent as Kioxia dived over 11 percent and Advantest plunged more than 13 percent, according to CNA. SoftBank Group lost more than 9 percent.
The Korean won weakened to 1,350 per U.S. dollar by late morning, down 7.7 won from the previous close, Yonhap reported.
In a video published by YonhapnewsTV, analysts discussed the market rout and its implications for semiconductor stocks.