Famed hedge fund investor Bill Ackman in the fourth quarter sold more than 3 million shares of Corrections Corp. of America. Ackman's Pershing Square Capital Management, which bought more than 9 percent of CCA (Ticker: CXW) in the fall of 2009 and added to the stake early last year, now owns 7.2 percent of the Nashville-based prison manager. In early December, Ackman said he still found the stock "attractive."