SEOUL, South Korea — A rout in artificial intelligence stocks deepened Thursday, sending South Korea’s main index down more than 8% and forcing a market-wide trading pause as investors weighed hotter U.S. inflation and the heavy borrowing behind the AI buildout.
The Kospi closed down 8.1% at a six-month low. A circuit breaker kicked in just after 12:38 p.m. local time, stopping trading across the market for 20 minutes, and the smaller Kosdaq triggered its own halt. It was the first day since July 29 that both exchanges hit circuit breakers.
Memory chipmakers took the worst of it. SK hynix lost about 11%, dragging its market value below 1,000 trillion won, while Samsung Electronics dropped more than 9%. In Tokyo, the Nikkei 225 fell 4.9% as SoftBank, a major OpenAI backer, slid 10% and memory maker Kioxia sank 11%.
The slide followed a rough Wednesday on Wall Street, where the Nasdaq Composite lost 1.9% and the S&P 500 fell 1.1%, its weakest session since July. Fresh data showed U.S. consumer prices rose 3.7% in September, the fastest pace since May, and analysts said the gains were broad rather than limited to fuel.
That reading has traders betting the Federal Reserve could raise interest rates again, possibly as soon as the end of this month. Earlier this week, the International Monetary Fund warned that a sharp drop in AI share prices could threaten global financial stability, with Asian markets among the most exposed.
Taiwan chip giant TSMC slipped 2% even after posting another record quarterly profit. Stocks in mainland China also weakened, and U.S. futures tied to the Nasdaq 100 pointed about 1% lower ahead of Thursday’s open.
