Microsoft co-founder Bill Gates has been ranked as the wealthiest person in America for the 14th year in a row.
Bill Gates earned his $59bn fortune from Microsoft
Forbes magazine put Gates' fortune at $59bn, with investment guru Warren Buffet in second place with a net worth of $52bn.
Casino magnate Sheldon Adelson and software tycoon Larry Ellison remained at third and fourth place on Forbes' list of the 400 richest Americans.
It took a net worth of at least $1.3bn to earn a spot in the rankings.
Google founders fifth
For the first time since 1989 there were no members of Walton family, which established Wal-Mart Stores, in the top 10.
They were displaced by Google founders Sergey Brin and Larry Page, who came in joint fifth place, with fortunes of $18.5bn apiece.
Investor Kirk Kerkorian was the biggest gainer on the list, his fortune rising by more than $9bn in the past year to $18bn, putting him in seventh place.
"Wall Street really led the charge this year," said Matthew Miller, editor of the Forbes list. "God only knows if they'll be on it next year. It really just depends on what the market does."
The collective net worth of the 400 billionaires totalled $1.54 trillion - more than Canada's GDP.