South Korean stocks fell more than 4% on Thursday, dragged down by a sharp decline in technology shares and persistent concerns over the profitability of artificial intelligence investments. The Korean won strengthened against the US dollar during the session.

The benchmark Korea Composite Stock Price Index (KOSPI) closed 4.58% lower, dropping 301.88 points to 6,296.38 points. It touched an intraday low of 6,238.32 points. The decline followed two consecutive sessions of gains—Tuesday and Wednesday—when the index rose 1.62% and 3.76% respectively, as fears over AI earnings had temporarily eased.

The KOSPI opened 1.81% lower before extending losses. At 10:18 a.m. local time, the Korea Exchange triggered a sell-side circuit breaker on the KOSPI, halting program trading of its constituent stocks for five minutes as the sell-off accelerated.

Overnight on Wall Street, investors dumped major Nasdaq-listed technology companies, including Alphabet (Google) and Advanced Micro Devices (AMD). Concerns that massive investments in AI infrastructure may not generate sufficient returns pulled the Nasdaq Composite down by 0.83%.

In contrast, signs of easing tensions in the Middle East lifted the Dow Jones Industrial Average by 0.49%, pushing it to a record high.