As seen in the news: Carly Fiorina finally creates some shareholder value by resigning. The value of HP went up by about $5 billion as a result.
Reminds me of this, from September 2003: Motorola CEO Resigns; Five Analysts Issue Upgrades (MOT, 12.06, up 0.97).
After Chris Galvin resigned, Motorola finally spun off its semiconductor division, like Wall St had been demanding for years. MOT subsequently rose to over $20 (albeit mostly because of improvements in the cell phone business).
No matter how unpopular CEOs are among the rank and file, when they go it's because Wall Street doesn't like them.