(MONEY Magazine) – We like our celebrities to live large and then some, whisked about in private jets and limos, draping themselves in serious bling and making impossible demands on hotel staff. Yet we grumble when CEOs make like movie stars and demand corporate jets. Is that fair? Survey says: Yes!

David Yermack, a finance professor at New York University, looked at several hundred large public companies over a period of 10 years. Those that allowed their CEOs to travel on company planes underperformed their market benchmarks by 4% a year --4! Percent! A Year!--a result, Yermack laconically observes, that's "much larger than could be explained by the direct cost of the resources consumed."

The problem? CEOs' fondness for perks may be a symptom of much wider corporate bloat. In fact, Yermack reports, public companies with jet-set CEOs report as much as $40,000 less in sales per employee than their non-jet-using rivals. Yermack notes that jet-abusing CEOs tend to be older and less educated than those merely flying first class. The worst corporate-flight abusers? Members of a company's founding family, natch. --D.F.