Major chip stocks fell sharply in US and Asia as an AI-related sell-off deepened. South Korea's Kospi index dropped 10.8% after a temporary halt, led by Samsung Electronics and SK Hynix falling over 13%. Nvidia fell 5% in New York, losing its position as the world's most valuable listed company to Apple.

The tech-heavy Kospi has been halted multiple times this year via circuit breakers. After doubling to mid-June, it lost around a third of its value. Japan's Nikkei 225 closed almost 4% lower. Jane Sydenham at Rathbones noted the Korean market is "very concentrated" in Samsung and SK Hynix, with many investors using debt, exaggerating corrections.

The sell-off was triggered by reports Nvidia is in talks to provide $250bn for OpenAI's data-center project. Apple rose ~25% this year, overtaking Nvidia as most valuable company. Cheng Chye Hsern at Providend said Apple appeals as it's "not taking part in the AI race." Investors worry whether massive AI spending will earn proper returns.

Competition concerns from China also weigh. CXMT (Chang Xin Memory Technologies) shares soared nearly 470% on Shanghai debut, planning to boost DRAM production for AI data centers. European markets shrugged off AI concerns, with FTSE 100, Cac 40, and Dax 40 up ~0.6%, having less AI exposure.