When activist investor Daniel Loeb announced in October he'd sold his Sony Corp. stake, executives at the company's Culver City, California, studio lot expressed relief.

"Sit by the side of the river long enough, and the bodies of your enemies will float by," Tom Rothman, chairman of Sony's TriStar Productions venture, wrote in an Oct. 21 email to Michael Lynton, Sony's top U.S. executive, and Amy Pascal, who runs the film business. The message is among thousands of documents released this month by hackers who targeted the entertainment unit.

"Champagne for all," wrote Sony Pictures Chief Financial Officer David Hendler on Oct. 9 after finding out that Loeb had sold.