But the lower CEO rating hardly puts Ballmer's job in jeopardy, said a Microsoft watcher.

"As long as Steve Ballmer has the second-largest block of stock and the backing of Bill Gates, he's not going anywhere except under his own power," said Rob Helm, an analyst with Directions on Microsoft, an industry research firm that focuses on the Redmond, Wash. developer.

The index, which was created by analysts at Chicago-based Applied Finance Group and a New Jersey consultancy called Great Numbers, was published by magazine, which issued its third-annual numbers today.

The rankings attempt to rate "business leaders who have performed best in creating true economic value" for their firms, said Michael Burdi of Applied Finance Group and Drew Morris of Great Numbers.

Dubbed the (WCI), the rankings use a concept called "economic margin," which measures the degree to which a company makes money above and beyond its risk-adjusted cost of capital.