Key facts
- KOSPI fell 7.57% to 5,554.22, its longest losing streak since September 2024.
- Trading halted for 20 minutes after KOSPI dropped more than 8%.
- US CPI rose 0.6% in September, fueling inflation and rate hike concerns.
South Korean stocks plunged more than 7 percent on Thursday, Oct. 15, 2026, as major chipmakers extended losses. The benchmark Korea Composite Stock Price Index (KOSPI) fell 7.57 percent to 5,554.22, marking its seventh consecutive session of declines. The sell-off prompted the Korea Exchange to activate a sell-side sidecar and a circuit breaker, halting trading for 20 minutes after the KOSPI dropped more than 8 percent from the previous session's close. Concerns over the sustainability of artificial intelligence-related investments and potential Federal Reserve rate hikes due to persistent inflation, evidenced by a 0.6 percent monthly rise in U.S. CPI in September, dampened investor sentiment.