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

The US will impose a tariff of 35 per cent on Canadian goods from August 1, Donald Trump said in a letter late on Thursday.

US stocks’ record highs obscure the risks Donald Trump poses to the world’s biggest economy, according to big investors and senior bankers who have warned over growing “complacency” in the markets.