Kirk Kerkorian's Tracinda said Friday it will tender for up to 16 percent, or 21.8 million shares, of oil refiner Tesoro at $64 per share.
The offer price represents an 11.9 percent premium over Tesoro's closing stock price of $57.20 on Thursday, said Tracinda, the investment company of billionaire financier Kerkorian.
Tesoro shares gained $8.60, at $65.80 on the New York Stock Exchange.
Tracinda currently owns 5.5 million shares of Tesoro common stock, or about 4 percent of the outstanding shares, the company said. Tracinda's average cost for those shares was about $52.23 per share.