Trump's action to bulk up protections for American steel and aluminum producers restores effective global tariffs of 25% on all imports of the metals.

President Trump imposed a 25 percent tariff on metal imports. The move is expected to raise costs for U.S. manufacturers of cars, solar panels and other products, potentially slowing the economy.

The move came after Ontario backed off imposing a surtax on U.S.-bound electricity, capping a rollercoaster day on Wall Street.