Baku, October 2, AZERTAC

America's top 400 billionaires are now richer than ever, boasting a record-smashing combined wealth of $2.34trillion, up $50billion from a year ago, according to the latest issue of Forbes Magazine, according to Dailymail.

Microsoft founder Bill Gates continued to dominate the prestigious list for the 22nd year in a row with a $76billion fortune, retaining his No 1 spot despite losing $5billion from 2014.

But it was Amazon CEO Jeff Bezos who has emerged as the biggest overall gainer, adding a whopping $16.5billion to his war chest in a single year after his company posted a quarterly profit in July.

The 51-year-old CEO's $47billion nest egg catapulted him into the fourth spot on this year's list, 11 positions up from 2014.

Facebook CEO Mark Zuckerberg made it into the top 10 list for the first time ever, landing at No 7 on the strength of his impressive $40billion fortune. Last year, the social-media wunderkind only barely cracked the list, coming in 10th.

In all, 25 newcomers made it into the ranks of America's wealthiest billionaires, including 25-year-old Evan Spiegel (#327) of Snapchat, the youngest on the list, worth $2.1billion, Brian Chesky (#194) of Airbnb at $3.3billion and Bill Haslam (#327), governor of Tennessee, at $2.1billion.

Travis Kalanick (#80), the tech guru behind the popular ride-sharing service Uber, was the biggest percentage gainer, doubling his fortune to $6billion in a single year.

The old guard of the annual Forbes list remained largely intact, led by Gates, 58, and his friend Warren Buffet, the 85-year-old CEO of Berkshire Hathaway ($68billion), who has occupied the second spot on the list since 2001.

Despite leaving his post as CEO of the software company Oracle Corp last year, Larry Ellison has retained his No 3 spot on the Forbes list, with a $47.5billion net worth.

Charles and David Koch, co-founders of Koch Industries, a giant company with interests in the oil industry, building and manufacturing, this year tied for fifth place, each bringing to the table a $41billion fortune.

Jim, Alice and Christy Walton, scions of the Walmart dynasty, each dropped a couple of spots from last year, with only Sam Walton's 67-year-old son making it into the top ten on the strength of his $33.7billion net worth.

At age 31, Elizabeth Holmes, founder of the ground-breaking blood-testing company Theranos, became the youngest woman on the list (#121, $4.5billion), while the oldest billionaire was 100-year-old David Rockefeller Sr, who landed in the 211th spot with a net worth of $3billion.

The cost of admission to the 2015 list was the highest ever at $1.7billion, up from $1.55billion a year ago. Because of the bar being so high, 145 American billionaires didn't make the cut, among them Elaine Wynn, co-founder of the Wynn Las Vegas hotel, and Urban Outfitters co-founder Richard Hayne.

The average fortune on the list was $5.8billion, up from $5.7billion last year.