Microsoft co-founder Bill Gates has been named as the wealthiest person in the US for the 17th year in a row.

Forbes magazine put his fortune at $54bn (34.5bn pounds), with investment guru Warren Buffet second with $45bn.

Software tycoon Larry Ellison was in third place, while Wal-Mart heir Christy Walton was fourth on Forbes' list of the 400 richest Americans.

It took a net worth of at least $1bn to earn a spot in the rankings - up from $950m in 2009.

The collective net worth of the 400 billionaires rose by 8% from 2009, totalling $1.37 trillion - approximately the same as the GDP of Spain or Canada.

Those gaining wealth in the list included Facebook co-founder Mark Zuckerberg, whose wealth grew by 245% to $6.4bn, the report said, putting him at 35 in the list.

His fellow co-founder Dustin Moskovitz is the youngest to make the top 400. The 26-year-old is eight days younger than Mr Zuckerberg and one of 16 new entrants to the list, which also includes another Facebook figure, Eduardo Saverin.

Full story: BBC News