Stockmarkets had their worst trading session since early August’s rout amid more fears of an economic slowdown. Tech companies suffered the most, led by Nvidia. It shed $279bn in market value, the most ever by one company in one day. Its stock fell again on reports that the Department of Justice had subpoenaed it in an antitrust investigation, which the company later denied. Intel’s stock dropped by 7% amid speculation that is about to be booted off the Dow Jones Industrial Average. The NASDAQ Composite fell by 3.3%. The sell-off spread to Asian and European markets.