The president stopped short of putting a 50 percent tariff on refined copper, as he had threatened earlier this year. The market reaction was swift anyway and prices tumbled.

The Trump administration says that the tariffs on metals imports are aimed at boosting domestic industries and addressing "trade imbalances."

The president stopped short of putting a 50 percent tariff on refined copper, as he had threatened earlier this year. The market reaction was swift anyway and prices tumbled.

Move roils US prices as new policy falls short of US president’s initial threats to introduce sweeping new levy

New tariffs apply mostly to semi-finished copper products while exempting refined forms of the metal that comprise the US’ chief copper imports.

Raw copper materials will not face the high duty that had been expected, but consumer goods prices may still be impacted.