Nvidia's shares plunged almost 7% in after-market trading, amid a broader slump in global markets as Trump's new ban intensifies a U.S.-China tech war.

President Donald Trump’s administration has barred Nvidia Corp. from selling its H20 chip in China, an escalation of Washington’s tech battle with Beijing that will cost the company billions of dollars and hamstring a product line it explicitly designed to comply with previous US curbs.

Wall Street index futures dropped on Wednesday and chip darling Nvidia slumped after the company flagged steep charges from new U.S. curbs on chip exports to China, fuelling worries about the fallout of an escalating trade war.