After nearly doubling in value over the last week and closing at a record high Wednesday, shares of MP Materials are sinking premarket Thursday after the rare earths miner announced plans to sell new stock.

MP Materials said on Wednesday it would sell $500 million of its common stock, a day after the U.S. rare earths miner inked a supply deal with Apple .

MP Materials Corp., a rare earth materials company, is seeing its stock price rise on news of a major commitment from tech giant Apple.

MP Materials shares remain in focus after soaring 20% yesterday on news that Apple plans to invest $500 million in the rare earths firm, news that came just days after the Department of Defense took a stake in the company.

However, it’s not just the government rushing to ensure rare earth supply. Apple (NASDAQ: AAPL) has one-upped the Pentagon by announcing a $500 million agreement with MP Materials to secure recycled rare earth magnets.

The Cupertino tech giant has inked a $500 million deal with Mountain Pass’ owner and operator MP Materials, the two companies announced on Tuesday, in a move that will help Apple onshore a part of its sprawling supply chain.

MP Materials, which has the only operational rare earths mine in the U.S., has drawn interest as a challenger to China's dominance from investors ranging from the Pentagon to tech giant Apple in recent days.