A wheel loader operator fills a truck with ore at the MP Materials rare earth mine in Mountain Pass, California, January 30, 2020.
Steve Marcus | Reuters
The Defense Department will become the largest shareholder in rare earth miner MP Materials after agreeing to buy $400 million of the company's preferred stock.
Shares of MP Materials jumped more than 40% premarket on the news.
This is a developing story. Please check back for updates.