Japan's benchmark Nikkei index tumbled 4.2% on Monday, erasing roughly $335 billion (₹32.05 lakh crore) from the investors' wealth in a single day, Bull Theory reported. Technology and AI-related stocks, including SoftBank Group, Tokyo Electron and Kioxia Holdings, led the decline as profit-taking was triggered by losses in their US counterparts. South Korea's stock market also crashed on Monday.