LAS VEGAS – Billionaire investor Kirk Kerkorian’s Tracinda Corp. said Wednesday that it plans to boost its majority stake in casino operator MGM Mirage Inc. even as it sells some shares in General Motors Corp., the world’s biggest automaker. Tracinda – which is solely owned by Kerkorian – said it would offer $825 million in cash for up to 15 million shares in MGM Mirage, raising its stake to 61.7 percent. The offer of $55 a share represented a premium of more than 12 percent premium over MGM Mirage’s closing stock price of $49 on Tuesday. MGM Mirage shares surged $5.21, or 10.6 percent, Wednesday to close at $54.21 on the New York Stock Exchange. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! AD Quality Auto 360p 720p 1080p Top articles1/5READ MORESurfer attacked by shark near Channel Islands calls rescue a ‘Christmas miracle’“This tender offer demonstrates our confidence in MGM Mirage and its management and our commitment to the company’s future,” a Tracinda representative said in a statement. Tracinda already holds 158.4 million shares, or 56.3 percent of the company’s outstanding stock. Kerkorian, 89, has expanded his casino holdings since opening The International in 1969, one of three huge hotels he opened in Las Vegas that were the largest ever built at the time. He later orchestrated the merger between MGM Grand and Steve Wynn’s Mirage Resorts Inc. The renamed MGM Mirage Inc. later acquired Mandalay Resort Group. Meanwhile, Tracinda said in a filing with the Securities and Exchange Commission that it would sell 14 million shares in GM this week for $462 million, reducing Kerkorian’s investment in the company’s stake to 7.4 percent from 9.9 percent. GM shares fell $1.52, or 4.7 percent, to close at $31.09 on the New York Stock Exchange. MGM Mirage, the world’s second-largest casino company after Harrah’s Entertainment Inc., owns the MGM Grand, Bellagio and other casinos in Las Vegas, as well as gambling properties in other Nevada cities and Atlantic City, N.J.