South Korean and Japanese equities plunged after a sudden reversal in global AI sentiment and macro developments. In Seoul, Samsung Electronics fell 7.4% and SK Hynix dropped 10.1% intraday; the two memory-chip makers account for roughly half of KOSPI market capitalization. KOSPI slid more than 9% intraday and triggered a 20-minute trading halt — the fourth such pause this year. In Tokyo, the Nikkei 225 fell over 3%, led by SoftBank and Kioxia, down about 10% and 14% respectively. Both markets h

South Korean and Japanese equities plunged after a sudden reversal in global AI sentiment and macro developments. In Seoul, Samsung Electronics fell 7.4% and SK Hynix dropped 10.1% intraday; the two memory-chip makers account for roughly half of KOSPI market capitalization. KOSPI slid more than 9% intraday and triggered a 20-minute trading halt — the fourth such pause this year. In Tokyo, the Nikkei 225 fell over 3%, led by SoftBank and Kioxia, down about 10% and 14% respectively. Both markets had recently hit multiple record highs on AI optimism, progress in US–Iran talks and expectations of BOJ tightening; analysts warn the chip names’ rapid run-up has left valuations elevated and exposed to semiconductor cyclical risk.