President Donald Trump mentioned Tuesday — almost in passing — that he planned to impose a 50% tariff on copper imports. It still hit like a bombshell, with potential to shake up U.S. efforts to expand, develop and deploy artificial intelligence.

Prices for the metal hit a record high after the president suggested a higher rate than many analysts were expecting.

President Donald Trump said Tuesday he’s imposing a new 50% tariff on all copper. However, it’s unclear when the new tariff would take effect.