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 launched a $500M public offering of common stock, and expects to grant a 30-day underwriters option to purchase up to an additional 15% of shares to be sold in the offering.

KEY TAKEAWAYS Shares of MP Materials are surging in early trading Tuesday after Apple said it would invest $500 million in the owner of the U.S.’s only operational rare earths mine.The move by the iPhone maker to ramp up its supply chain at home comes days after the Department of Defense took a 15% stake in the Las Vegas-based rare earths