LONDON (Reuters) - Price premiums for aluminium on the physical market in the United States soared to a record high above $990 a metric ton on Tuesday after President Donald Trump said he would double planned tariffs on Canadian metal to 50%.

Canadian smelters account for the bulk of primary and alloyed aluminium exports to the United States, 70% of 3.92 million tons last year, according to information provider Trade Data Monitor.

The doubling of the levies, in response to the Canadian province of Ontario placing a 25% tariff on electricity coming into the U.S., take effect from Wednesday.

Consumers buying aluminium on the physical market typically pay the London Metal Exchange (LME) benchmark aluminium price plus a premium that would covers taxes, transport and handling costs.

The U.S. Midwest duty-paid aluminium premium jumped to 45 U.S. cents per lb, or more than $990 a metric ton, on Tuesday. It has climbed more than 70% since the start of 2025.