Copper futures (HG1:COM) extended their rally on Thursday, rising around 2% as traders reacted to U.S. President Donald Trump’s announcement of a 50% tariff on imported copper, set to take effect on August 1.

President Trump will wield 50% copper tariffs on August 1 as he promises more to come with countries such as Brazil in the crosshairs. Nvidia scores the first $4 trillion market cap milestone, lifting the Nasdaq to a record.

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

The U.S. copper price premium over the global benchmark soared 138% on Tuesday to a record high after U.S. officials announced potential 50% import tariffs on the metal. Copper has been flooding into the U.

Trump said on Tuesday that he would impose a 50% tariff on copper. Though the remarks were light on specifics, his comments sent the metal to all-time highs.

“The U.S. has been sucking in lots of copper that it didn’t really need from around the world,” Albert Mackenzie is a copper analyst at Benchmark Mineral Intelligence. President Trump had signaled that the tariffs were coming months ago, prompting many U.S. buyers to stockpile copper ahead of time.

Carlos Gutierrez, former Commerce Secretary, told CNBC’s Emily Tan on “The China Connection” that the U.S. reliance on copper imports is a “vulnerability, but [the U.S. doesn’t] have the capacity right now to offset imports.

President Trump’s proposed 50% tariff on copper imports would likely prove a boon for companies that mine copper in the U.S. So the question for investors is: Which stock should they buy to take advantage?