LONDON (Reuters) - Premiums for consumers buying aluminium on the physical market in the United States soared on Monday after U.S. President Donald Trump said he planned to increase tariffs on imported steel and aluminium to 50% from 25%.

The U.S. is heavily reliant on aluminium imports. About half of all aluminium used in the country for transport, packaging and construction is delivered from elsewhere, with the vast majority coming from Canada. The new tariffs are due to take effect on June 4.

Buyers on the physical market usually pay the London Metal Exchange (LME) benchmark aluminium price plus a premium covering taxes, transport and handling costs.

The U.S. Midwest duty-paid aluminium premium reached $0.58 per lb, or $1,279 a metric ton, on Monday. That was a 54% jump from Friday and 164% growth since the start of 2025.

Part of Monday's growth was amplified by June 2 being the first trading day of the new month, when regional premiums often make a strong move.

Goldman Sachs said the premium would need to rise to between $0.68 and $0.70 per lb to fully reflect the 50% import tariff. LME benchmark aluminium was last up 0.2% at $2,448.5 a ton.