KOSPI plunges 5% on Alphabet shock; Samsung, SK Hynix lead losses

South Korea's stock market plunged on Friday morning following Alphabet's weak earnings, with the KOSPI falling over 5% and triggering a sell-side circuit breaker. Samsung Electronics dropped 6% and SK Hynix fell 8%. The KOSPI index fell 313.02 points (5.27%) to 5,624.64 by 11:30 a.m., after opening down 2.99%. The Korea Exchange halted program sell orders for five minutes at 10:04 a.m. when the KOSPI200 futures index dropped 5.12%, marking the first sell-side car in 11 trading days. Foreign and institutional investors turned to selling after initial buying, while most large-cap stocks declined. The selloff reflects Alphabet's 12.64% stock plunge on October 29, triggered by third-quarter earnings missing expectations and accelerating AI-related cash burn. This sparked concerns across AI infrastructure and software sectors, dragging down all three major U.S. indices, with tech stocks hit hardest.