KOSPI plunges 8% triggering trading halt as AI spending fears hit South Korea and Japan

South Korean and Japanese stocks plunged Thursday as investors scrutinized AI infrastructure financing, with the KOSPI falling 8% and triggering a 20-minute trading halt. Samsung Electronics dropped 9.5% and SK Hynix 11.4%, while Japan's Nikkei 225 fell 4.8%. Higher US inflation provided the immediate catalyst, but deeper concerns center on whether companies funding AI infrastructure can sustain spending. The KOSPI suffered most because Samsung and SK Hynix depend on data center operators' capital expenditures, with CoreWeave falling nearly 16% and Oracle about 9% on Wednesday. The Philadelphia Semiconductor Index dropped 4.3%, extending a near 12% decline over nine sessions. TSMC's upcoming earnings will test whether physical AI demand remains intact, as ASML said equipment demand will likely exceed supply through 2028.