Comex copper for July delivery jumped 66.05 cents per pound, or 13%, to close at $5.645. That's a record high and the biggest single-day gain ever for copper, according to Dow Jones Market Data. The metal is up 41.6% year to date and up 23.3% over the past 52 weeks. In after-hours trading, the metal traded at $5.48 per pound, according to FactSet.

Copper prices notched record highs Tuesday after President Trump signaled plans to impose a 50% tariff on the commodity. Why it matters: The price of copper figures into a wide variety of goods, including building construction,