Japanese and South Korean stock markets closed lower, with South Korean stocks falling more than 5%.

South Korea’s KOSPI closed down 300.15 points, or 5.28%, at 5,383.65 on Nov. 5, its lowest close since April 3, while Japan’s Nikkei 225 fell 1,110.73 points, or 1.79%, to 61,077.90, as AI-regulation concerns hit chip and defense stocks. The KOSDAQ dropped 5.11%, triggering sidecar circuit breakers that briefly halted program trading, with SK Hynix down 9.45% and Samsung Electronics down 7.56%. The scale of the Korean selloff matters because chipmakers dominate the index and a 5% single-day drop is rare outside crisis periods. Watch whether Seoul follows through with stabilization measures and whether AI-policy headlines continue to drive semiconductor valuations across Asia.