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

The Defense Department is buying $400 million of stock in rare-earth mining company MP Materials as it seeks to boost domestic sources of the critical minerals.

Shares of the mining company soared 50% in early trading at $45.10, while the S&P 500 and Dow Jones Industrial Average were flat and down 0.2%, respectively. The agreements includ