The KOSPI opened down 4.31% before losses deepened to more than 6%, while Samsung and SK Hynix fell sharply and Japan’s Nikkei 225 also opened lower.
South Korea’s stock market fell sharply on June 5, with the benchmark KOSPI opening down 372.6 points, or 4.31%, at 8,266.81 before losses deepened to more than 5% and triggered an intraday circuit breaker; the index was down over 6% at press time. Samsung fell 5% in early trading and SK Hynix dropped 7% at the open before falling as much as 9%. Japan’s Nikkei 225 also opened lower, down 486.82 points, or 0.72%, at 66,983.87. Reports linked the South Korean selloff to softer-than-expected AI guidance from Broadcom and a research note about Nvidia Rubin memory cuts, which appeared to weigh on sentiment toward AI-linked semiconductor suppliers.