That's according to research firm Wealth-X , which recently released its annual Billionaire Census , a study of the global billionaire population.

In fact, nearly a third (30%) of today's billionaires don't have a bachelor's degree.

Research by Steve Siebold, who spent three decades studying over 1,200 of the world's wealthiest people, parallels Wealth-X's findings.

"Many world-class performers have little formal education, and have amassed their wealth through the acquisition and subsequent sale of specific knowledge," he writes in his book, "How Rich People Think."

On the flip side, "the masses are convinced that master's degrees and doctorates are the way to wealth," Siebold notes.

According to Wealth-X, only 22% of today's billionaires have a master's degree; 13% have an MBA and 10% have a Ph.D.; even fewer have a law degree (3%) or a degree in medicine (1%).