(Bloomberg) Stocks that soared recently in South Korea on researchers’ claim of a breakthrough in superconductor technology tanked Friday as experts sought proof while the local exchange escalated its warning on the trading frenzy.Most Read from BloombergTrump Cites Self Incrimination Concern in Lawsuit Against CohenQQQ Churns in Late Hours on Apple, Amazon Earnings: Markets WrapElon Musk Says Treasury Bills Are ‘No-Brainer’China Official’s Call to Save Xi’s City Angers Flood VictimsThe Stran