For the first time in the history of the Forbes rich-list all of the 400 wealthiest Americans are now billionaires.
The magazine's annual rundown of individual tycoon's fortunes reveals that everyone on the list has a personal fortune of at least $1 billion (£0.53 billion), while the elite's combined worth rose $120 billion (£63 billion) to $1.25 trillion (£0.66 trillion).
Forbes claims that "surging" gains from real estate and oil have driven this year's list, which features 28 new additions.
There are no surprises as to who sits at the top of the list, with Microsoft founder and chairman Bill Gates revealed to possess $53 billion (£27.9 billion).
The 50-year-old announced in June that he was planning to step down from daily duties at the company by 2008 to devote his time fully to his charity Bill and Melinda Gates Foundation.
But the software architect was not the highest climber on the list, with casino mogul Sheldon Adelson almost doubling his wealth to $20.5 billion (£10.8 billion).
His Las Vegas Sands stock has increased by 125 per cent since its public offering at the end of 2004, Forbes says, meaning Mr Adelson has made almost $1 million every hour since the 2004 rich list.
The highest placed woman in the list is Christy Walton at sixth place. Ms Walton, the widow of Wal-Mart heir John has an estimated fortune of $15.6 billion (£8.2 billion).
Also on the ascendancy are Google founders Sergey Brin and Larry Page, who are at 12th and 13th with $14.1 billion (£7.4 billion) and $14 billion (£7.3 billion) respectively.
Top five richest Americans
Bill Gates $53 billion, Microsoft Warren Buffett $46 billion, Berkshire Hathaway Sheldon Adelson $20.5 billion, casino and hotel ventures Lawrence Ellison $19.5 billion, Oracle Paul Allen $16 billion, Microsoft and investments