Big and getting bigger: Bill Gates has plenty to smile about

2004 is the eleventh year in a row that Mr Gates has topped Forbes's list of the 400 wealthiest people in the US.

Investment guru Warren Buffett is in second place, with $41bn (�23bn); Mr Gates has earned $48bn.

The combined net worth of the top 400 is $1 trillion, $45bn more than last year. The magazine said the rise was due to an improving global economy.

Out of the 400 on the list, a record 313 are billionaires.

Earning power

Technology companies still put in a good showing, despite the problems the industry has faced over the past couple of years.

Forbes Top 10 by net worth 1 Bill Gates $48bn 2 Warren Buffett $41bn 3 Paul Allen $20bn 4 Alice Walton $18bn 5 Helen Walton $18bn 6 Jim Walton $18bn 7 John Walton $18bn 8 Robson Walton $18bn 9 Michael Dell $14.2bn 10 Larry Ellison $13.7bn

Microsoft co-founder Paul Allen is at number three, with computer maker Michael Dell at number nine and Oracle boss Larry Ellison at 10.

Sergey Brin and Larry Page, the founders of internet search engine Google, make the 400 for the first time after floating their company on the stock market.

The youngest people on the list, the two are tied at number 43 in the list with $4bn each.

Five places in the top 10 are taken up by the Walton family, which gets its wealth from the Walmart supermarket chain.

The biggest percentage gainer is casino operator Steve Wynn, who doubled his worth to $1.3bn.

Amazon.com's Jeff Bezos who lost the most, held on to his 38th placing despite shedding $800m.

Forbes magazine is due to publish its list on 11 October.