In February 2008, Microsoft Corporation made an unsolicited bid to acquire Yahoo! for USD $44.6 billion. Yahoo! subsequently formally rejected the bid, claiming that it "substantially undervalues" Yahoo! and was not in the interest of its shareholders. Three years later, Yahoo! had a stock market capitalization of USD $22.24 billion. Carol Bartz replaced cofounder Jerry Yang in January 2009. In September 2011 she was removed from her position at Yahoo! by the company's chairman Roy Bostock (via phone call), and CFO Tim Morse was named as Interim CEO of the company.