More billionaires got their undergraduate degrees from the University of Pennsylvania than any other school, according to a new study from Wealth-X.

Harvard is often ballyhooed as the No. 1 school for producing billionaires, but that's taking its graduate programs into account. Two years ago, Forbes counted 32 billionaires with graduate degrees from Harvard.

Just for bachelor's degrees, Penn, including its Wharton School, can count 25 billlionaires, according to Wealth-X, followed by Harvard with 22, Yale with 20, the University of Southern California with 16, and Princeton, Cornell and Stanford, all with 14.

See: "46 billionaires who went to Philadelphia-area colleges"

Foreign universities begin to appear after that, with the University of Mumbai tying Berkeley with 12, and the London School of Economics and Political Science tying with Lomonosov Moscow State University with 11.

Unfortunately, Wealth-X offers no names, and Forbes' billionaire lists aren't searchable by university. So coming up with a complete list of names is problematic. Some 1,645 people made Forbes' list of the world's billionaires in March, and Wealth-X somehow found hundreds more -- 2,325.

The upshot: We seem to be missing four billionaires for Penn, another four for Princeton -- if Wealth-X's census is right.

Our recent list named 21 billionaires who got their undergraduate degrees at Penn/Wharton (as well another seven who got their MBAs at Wharton, and two Wharton dropouts, including Warren Buffett).

Manoj Bhargava, the India-born creator of 5-Hour Energy, went to Princeton, but he dropped out and is no longer a billionaire, according to Forbes. Princeton alums Peter Briger and Michael Novogratz dropped off the Forbes billionaire lists about five years ago, and Peter Lewis died last year.

See: "Meet 22 of the Philly area's super-rich"

Contact staff writer Peter Mucha at 215-854-4342 or Follow @petemucha on Twitter.