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,

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

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.