Japan's Nikkei was down more than 4.6 per cent close to midday, while South Korea's KOSPI fell 6 per cent at one point. HONG KONG: Tech companies led a sharp sell-off across Asia on Wednesday (Nov 5) as investors grow increasingly worried about an artificial intelligence bubble following a rally this year that has seen valuations hit record highs. Global markets have soared this year as an eye-watering flood of cash piled into companies linked to AI, including United States titans Nvidia ,