US equity markets tumbled as investors digested news of U.S. restrictions on chip exports to China and Federal Reserve Chair Jerome Powell's latest assessment of the economy - Dow dropped -700 or -1.73% Nvidia Corp -6.87% after disclosing in a filing with the Securities and Exchange Commission (SEC) after the close of the previous session that sales of its H20 chips to China would require licenses from the Department of Commerce “for the indefinite future”. The chipmaker said it would record charges in its fiscal first quarter of up to US$5.5B for inventory and cancelled sales.