April 9: Trump's higher "reciprocal tariffs" begin just after midnight. Hours later, the president says he is issuing a 90-day pause on those duties, except for China. Trump raises tariffs on Chinese goods from 104% to 145%, the highest rate so far this year.

Trump has sent letters to leaders of dozens of countries outlining the tariff levels set to begin on Aug. 1. In recent months, Trump has rolled back some of his steepest tariffs, meaning delays could be possible in the case of the Aug. 1 deadline. The Trump administration appears to have stood largely behind the deadline in recent days, however.

Alcoa Corp., the largest US aluminum producer, said tariffs on imports from Canada cost it $115 million in the second quarter, showing how US President Donald Trump’s trade agenda has affected the industry.

Trump on Monday signed a pair of presidential proclamations imposing 25 per cent tariffs on steel and aluminum, with no exceptions or exemptions. "It's a big deal.