Late Thursday, Trump posted a letter threatening to impose 35% tariffs on goods from Canada. The barrage of letters began on Monday, setting tariffs of 25% on goods from Japan and South Korea and 50% on Brazil.

Wall Street on Friday was poised for a negative open, with stock index futures down, as President Donald Trump slapped a 35% tariff on Canada and warned of further hikes if Ottawa retaliated. S&P 500 futures (SPX) -0.