Traders are scrambling to ship copper to the US to capitalise on a dislocation in commodity markets that has sent New York-traded prices surging above London and Shanghai ahead of potential tariffs on the metal.

US President Donald Trump late last month ordered the Commerce Department to conduct a probe into the copper market that could take months to complete. Still, the news sparked a rally in US copper prices as traders prepared for the possibility of tariffs being much larger than expected, and imposed much sooner.