Asian stocks today: South Korea's Kospi falls 5%, Japan's Nikkei 225 plunges 2% over AI concerns

Asian markets fell sharply on 2 July after a selloff in US chipmakers reignited concerns over elevated AI valuations. South Korea's Kospi plunged 5.36% at open, triggering a five-minute trading halt, while Japan's Nikkei 225 declined 2%. The Philadelphia Semiconductor Index had dropped 6.3% in the prior US session, and US index futures slipped 0.3% in early Asian trade. Brent crude eased 0.8% to 71 dollars per barrel, offering some relief to broader sentiment.