US stocks fell after Nvidia revealed costly new curbs on chip exports to China, and investors grappled with uncertainty over President Trump's trade policy.

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.

U.S. stock futures moved lower Wednesday morning as investors braced for another wave of geopolitical and earnings headlines. Nasdaq futures dropped more than 1%, with the S&P 500 off 0.5% and the Dow Jones Industrial Average flat.