Amazon stock plunged 8% in premarket trades Friday. The e-commerce giant reported second-quarter results that topped Wall Street's expectations, but gave a mixed outlook. For the current quarter, Amazon predicted sales of $176.75 billion at the midpoint of its range, compared with analyst expectations for $173.27 billion.

Markets are assessing the reshaped US trade landscape after Trump on Thursday laid out steep new tariffs for dozens of countries.