Apple's worst day in months turned into a full-blown reckoning for the artificial intelligence trade — and it didn't stay confined to Wall Street. By the time markets closed in Asia, South Korea's Kospi had been halted by a circuit breaker (an automatic pause exchanges use when prices fall fast enough to risk panic) after sliding 8%, while Tokyo's Nikkei dropped over 4% and Hong Kong's Hang Seng followed it down. Today's Daily Business Index — our daily 0-to-100 reading of global business health, where 50 is neutral — sits at 49.5, a step below neutral and down from the weekend. The reason: a synchronised loss of nerve in AI stocks outweighed genuinely good news on oil and US jobs.