Samsung and SK Hynix shed more than 12 per cent each, triggering an automatic 20-minute bourse-wide trading halt in the afternoon.   SEOUL: South Korea's KOSPI collapsed 10 per cent Tuesday (Jun 23) in an Asian stock market rout that followed a tech-led sell-off on Wall Street with investors again questioning a long-running AI-fuelled boom. The rout followed a sharp drop on Wall Street, where the Nasdaq sank more than 1 per cent as market giants Amazon, Nvidia and Microsoft were sharply down.