The planned 50% tariff on copper imports may turn out to be the biggest own goal of U.S. President Donald Trump's ongoing trade war with the rest of the world.

Donald Trump's mooted 50% tariff on copper imports into America has sharply exacerbated what was already a dislocation between New York and London prices for the metal. The chart shows that since Trump's inauguration traders have been placing a greater premium on the COMEX contract,

While the cost of copper is going up for American businesses and consumers, the rest of the world is scratching its head while it enjoys a considerable discount on the price of copper.

President Trump's threatened 50% copper tariffs have boosted prices for the metal in the U.S. far ahead of anywhere else, lifting the premium to roughly one quarter. Copper futures mainly trad

U.S. President Donald Trump broadened his global trade war on Tuesday as he announced a 50% tariff on imported copper and said long-threatened levies on semiconductors and pharmaceuticals were coming soon.