Harvard University has turned out more graduates who have reached ultra-high-net-worth status than any other university in the world, according to Wealth-X, the educational and research business development organization of ultra-high-net-worth (UHNW) individuals.

Wealth-X defines this demographic as those with $30 million or more in assets. All but three of the universities with the highest number of UHNW individuals are in the United States.

Harvard has the highest number of billionaires with 52 and the largest number of UHNW individuals with 2,964. That group has $622 billion in net worth. The University of Pennsylvania, which has 1,502 UHNW graduates with a total of $242 billion in assets, is a distant second in aggregate UHNW assets.

Of the top 20 universities in the world ranked by the number of UHNW alumni, the three that aren't in the U.S. are the University of Oxford with 401, the University of Mumbai with 372 and the University of Cambridge with 361.

In the U.S., only three who made the list are public universities: the University of Virginia with 499, the University of California, Berkeley, with 447 and the University of Michigan with 410.

Stanford University (1,174), Columbia University (889) and New York University (828) round out the list's top five.

“American universities dominate the rankings largely because these prestigious institutions have been able to attract global talent,” says Wealth-X President David S. Friedman. “Most of the ultra-high-net-worth alumni have self-made fortunes, underscoring how these institutions have served as launching pads for many of the world’s most successful entrepreneurs and companies.”

Northwestern University, which ranks 13th with 451 UHNW alumni, has the highest percentage of women in the group with 15 percent. The Massachusetts Institute of Technology, ranking 7th with 581 UNHW alumni, has the highest percentage of men at 98 percent.