The Pentagon is slated to become the largest shareholder in rare-earth miner MP Materials. The Department of Defense has agreed to buy $400 million of MP's stock and provide the Las Vegas-based miner with a $150 million loan,

The Defense Department on Thursday became the largest shareholder in MP Materials, which owns the only rare earth mine in the U.S., amid a surge in demand for rare earths mined in the U.S. as China has curbed its rare earth exports amid a trade war with the U.S.

Shares of the little-known mining company soared on Thursday on news that the Pentagon would become the largest shareholder.