The list of 10 billionaires was dominated by "technopreneurs" as six of them made their fortunes from technology or technology-related businesses, including Gates, Larry Ellison of Oracle and Facebook co-founder Mark Zuckerberg.
The 10 entrepreneurs are collectively worth USD 407.4 billion, accounting for about 20 per cent of the total ultra-rich wealth in America, according to Wealth-X, the global wealth intelligence and prospecting firm headquartered in Singapore.
The combined market capitalisation of these 10 individuals' primary companies is USD 1.7 trillion, which means they have created wealth that's four times what they themselves are worth.
Legendary investor Warren Buffett, who at 83 is also the oldest person on the list, was ranked second with an estimated wealth of USD 64.2 billion.
Buffett was followed by Ellison of Oracle with a net worth of USD 48.2 billion and businessman and Bloomberg LP founder Michael Bloomberg with USD 33.7 billion.
Sheldon Adelson, Chairman and Chief Executive Officer of the Las Vegas Sands Corporation, was ranked fifth with a net worth of USD 32.8 billion, while Google's Larry Page was placed sixth with a net worth of USD 31.3 billion.
Zuckerberg, 30, is the youngest person on the list and was placed seventh with a net worth of USD 30.9 billion, followed by Jeff Bezos, founder and CEO of Amazon.com (8th, USD 30.5 billion); Google's Sergey Brin (9th, USD 30.1 billion) and Carl Icahn (10th, USD 25.5 billion).
All the self-made entrepreneurs on the list are active in the world of philanthropy, and six of them have joined the Giving Pledge, a campaign initiated by Gates and Buffet to encourage the world's most affluent individuals to pledge at least half of their fortunes to charity, the Wealth-X report said.