U.S. equity futures traded lower heading into the final trading session of the week. The major futures indexes suggest a drop of more than 1% on the Nasdaq and 0.3% on the Dow. Amazon shares are down more than 6% in the premarket following quarterly results. Amazon beat investors' expectations on earnings per share, but came up short on Wall Street's revenue estimates. The e-commerce and tech giant also lowered its third-quarter outlook. Amazon's second-quarter earnings per share came in at $15.02, beating estimates by $2.80. The firm's sales hit $113.1 billion for the quarter, failing to hit the $115.4 billion predicted by analysts polled by FactSet.