Copper futures at New York’s Commodity Exchange fell by more than 22% - the highest ever, as traders recalibrated the value of metal in the US versus the rest of the world.

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

Copper traded in New York dropped about 18 per cent to $4.60 a pound in tumultuous trading after the president’s announcement. Futures had surged to a record high of nearly $6 earlier this month when Trump announced the copper tariffs, but declined to provide specific details on which products they would apply to.