U.S. President Donald Trump signed an executive order late on July 31 raising tariffs on Canadian imports not covered by the U.S.–Mexico–Canada Agreement to 35%, up from 25%. The increase, which took effect Aug. 1, also imposes a 40% duty on goods routed through third countries to evade the levy. The White House said the step responds in part to Canada’s alleged failure to curb fentanyl shipments. Canadian Prime Minister Mark Carney called the decision "disappointing" and said Ottawa will examine retaliatory measures to protect sectors such as lumber, steel, aluminum and autos. Ontario Premier Doug Ford urged a 50% counter-tariff on U.S. metals, while Washington signalled the rate could be revisited if Canada refrains from retaliation. The Canada move is part of a wider tariff blitz authorised in the same order that sets duties of 10% to 40% on nearly 70 trading partners. Most of those rates will apply after a seven-day grace period, and Mexico received a 90-day window to strike a broader accord while keeping its current 25% rate. Equity markets recoiled. The Dow Jones Industrial Average fell 542 points, or 1.23%, to 43,588.58, the S&P 500 slid 1.6% for its biggest single-day decline in more than two months, and the Nasdaq dropped 2.24%. An 8.3% plunge in Amazon shares following a weak cloud-computing outlook compounded the sell-off, while Treasury yields retreated as investors bet the Federal Reserve will cut interest rates as early as September.