Copper futures in New York surged after US President Donald Trump said he planned to implement a 50% tariff on imports of the commodity, a move that’s likely to spark massive supply-chain ripples through global metal markets.

Contracts on the Comex climbed as much as 17% on Tuesday, a record one-day spike. New York prices are now commanding an unprecedented 25% premium to equivalent futures in London, the market that sets global benchmark prices.