Copper prices have hit record highs as an ongoing trade war between the U.S. and its key trading partners threatens to squeeze supplies of the vital metal. Buyers in the U.S. have been stocking up on copper ahead of potential tariffs.

The most actively traded copper futures contract in New York hit $5.374 per pound Wednesday morning before settling at a record $5.24 per pound. Copper prices have soared 30% this

US prices of copper have been on a tear this year due to the fear that tariffs will be imposed on imports of the red metal. Futures prices have hit record highs on New York’s Comex, leading to a premium over the international benchmark in London — similar to the disconnect seen in the gold market.