(Reuters) - U.S. movie studio MGM Holdings is exploring a sale, a person familiar with the matter told Reuters on Monday. The movie studio behind the “James Bond” franchise has tapped investment banks Morgan Stanley and LionTree LLC and started a formal sale process, the source said, asking not to be identified. The company has a market value of around $5.5 billion, based on privately traded shares and including debt, the source added. The development was reported on.wsj.com/37DWKEq earlier by the Wall Street Journal. MGM Holdings said it had no comment.