Copper traders were caught flat-footed after refined copper was exempted from Trump's new tariffs. The exemption triggered a 20% drop in copper futures on the COMEX exchange. Traders now face excess inventory, with COMEX stockpiles at a 21-year high.

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

President Donald Trump signed executive actions on Wednesday imposing a 50% tariff on Brazil, a 50% tariff on certain copper products and suspending a tax perk for all countries that allowed cheap packages to fly into the US duty-free.