The creators of internet search engine Google have joined the Forbes magazine list of world billionaires.
Larry Page and Sergey Brin are worth $1bn each, Forbes says
Google founders Sergey Brin and Larry Page are among many new additions to the list, which has a record 587 names this year compared with 476 in 2003.
Forbes said the recovery in share prices over the past year had helped to swell the number of billionaires.
Microsoft chairman Bill Gates topped the list for the 10th year in a row, with investor Warren Buffett in second.
But the market recovery meant Mr Buffett closed the gap between himself and Mr Gates.
Bill Gates' wealth was estimated to have grown by 13% to $46.6bn (£25.3bn), although this is still well below the peak of $100bn in 1998.
Meanwhile Warren Buffett's estimated wealth surged by $12.4bn, Forbes said, to $42.9bn.
"After two years of significantly falling fortunes, we
really saw an uptick for just about everyone on the list," said Forbes associate editor Luisa Kroll.
In third place was Karl Albrecht, the German businessman behind the Aldi discount supermarket chain.
FORBES BILLIONAIRE LIST - TOP 10
1: Bill Gates - $46.6bn
2: Warren Buffett - $42.9bn
3: Karl Albrecht - $23bn
4: Prince Alwaleed Bin Talal Alsaud - $21.5bn
5: Paul Allen - $21bn
Joint 6th: Alice Walton, Helen Walton, S Robson Walton, John Walton, Jim Walton - $20bn
Saudi prince Alwaleed Bin Talal Al-Saud was fourth, closely followed by Microsoft co-founder Paul Allen.
The rest of the top 10 consists of the wife of Wal-Mart founder Sam Walton and four members of the Walton family - with each worth an estimated $20bn.
The two Google founders, Sergey Brin and Larry Page, have to make do with the more modest position of 552, with $1bn each.
And joining them at the same ranking is Harry Potter author JK Rowling.
Because the Forbes list measures wealth in terms of US dollars, the recent rise in the value of the euro against the dollar has lifted European fortunes.
This year sees 22 new European billionaires on the list, lifting the total to 164.
Rising oil prices have helped eight Russians to join the billionaire club, swelling the number of representatives from that country to 25.
But not all Russian billionaires are getting the chance to enjoy their money. Former Yukos chief executive Mikhail Khodorkovsky - with an estimated wealth of $15bn - is currently in jail charged with fraud and tax evasion.
And, although not rich enough for the billionaire list, Forbes includes Fidel Castro among a list of millionaire world leaders.
The veteran Cuban leader is valued at $150m, taking into account what it calls his lavish homes throughout the country and the $50m proceeds of the sale of the Havana Club rum company in 1993.