Barry Diller's People Inc. Offers $48.30 Per Share for MGM Resorts

People Inc. sent a letter to MGM Resorts International's board of directors proposing to acquire the company for $48.30 per share in cash, a deal that would value MGM at approximately $18 billion. People Inc., formerly known as IAC, already owns a roughly 26 percent stake in MGM Resorts and began investing in the casino operator nearly six years ago.

Barry Diller, chairman of People Inc., sits on the MGM Resorts board and said he would recuse himself from any board actions related to the proposed deal. In the letter, Diller stated that "we continue to believe the market materially undervalues the power and durability of MGM's assets."

MGM Resorts operates major Las Vegas properties including the Bellagio and Aria. The offer was announced on Monday. Shares of MGM Resorts rose roughly 11 percent in early trading following the news, while shares of People Inc. increased about 2 percent.

CNBC's Andrew Ross Sorkin previously reported that an offer could come as early as Monday.