Most Billionaires Ever in Forbes 400

The nation's billionaire's club may not be quite as exclusive as it once was.

There are now 313 billionaires in the country, the largest number ever and a huge jump over last year's 262 members, according to Forbes magazine (search), which Thursday released its annual ranking of the 400 richest Americans.

The combined net worth of the 400 rose $45 billion, reaching $1 trillion this year for the first time since 2000, before the dot-com bust.

Retaining the top spot was Microsoft founder Bill Gates (search), whose $48 billion in estimated wealth was up $2 billion from 2003. Gates was again followed by investor Warren Buffett (search) with $41 billion, the list's biggest dollar gainer with a $5 billion increase, and Microsoft co-founder Paul Allen, who held the No. 3 spot although his net worth fell $2 billion to $20 billion.

Members of the Walton family, whose fortune comes from Wal-Mart Stores Inc., again swept spots four through eight, with each having estimated wealth of $18 billion.

The only change in the top 10 came from Dell Inc.'s Michael Dell and Oracle's Lawrence Ellison, now No. 9 and No. 10 respectively after swapping places from 2003. Michael Dell had a net worth of $14.2 billion; Ellison, $13.7 billion.

There were 45 new names, including Google's Sergey Brin and Larry E. Page -- also the youngest members at 31. They tied for No. 43 with $4 billion each. Fifty-four people dropped off the list, including Disney's Michael Eisner.

The city with the most members is New York with 38; California is the top state with 98 members.

Donald Trump's net worth edged up to $2.6 billion, but he slipped to No. 74 from 71. Returning after a year's absence was Teresa Heinz Kerry, wife of Democratic presidential nominee John Kerry; her $750 million tied her for last place.

Forbes senior editor Peter Newcomb attributed the list's overall gains to the improving economy, as well as a good year in the financial sector and industries including food and wine.

If the economy's upward trend continues, "it won't be too long before our entire list consists of billionaires," he said.