Carlos Slim, the Mexican telecoms tycoon, is the richest person in the world, with a net worth of $68.5 billion, according to Bloomberg’s new index of billionaires.

Nine out of the 20 of the world's wealthiest are Americans, the richest and probably most famous of whom are Microsoft’s founder Bill Gates with $62.4 billion and Warren Buffett, the investment guru, with $43.8 billion.

Sweden, with a population of just eight million, sticks out with two people in the top 20: IKEA’s founder Ingvar Kamprad, with a fortune of $42.5 billion, and Stefan Persson, the chairman and the main shareholder of H&M, with $24.5 billion. Kamprad is also the richest person in Europe.

Eike Fuhrken Batista of Brazil has increased his fortune more than anyone in the past year. Batista’s net worth has risen by a third to nearly $30 million in the 12 months to 4 March.

Other countries represented in the index are France in the shape of Bernard Arnault and Liliane Bettencourt; India, with Mukesh Ambani and Lakshmi Mittal; China, with Li Ka-Shing; Spain, with Amancio Ortega Gaona, and Canada, in the shape of David Thomson.

That means that four people out of the 20 richest in the world are from the BRIC countries. Switzerland and the UK, which are both wealth management and private banking centres, are not represented, nor is Russia, whose capital Moscow boasts more billionaires than any other city in the world.

Two people in the index are women: Christy Walton, the American widow of the son of the founder of Wal-Mart, with a net worth of $24.9 billion, and Bettencourt, the French entrepreneur who is the main shareholder in L'Oréal and has a $22.4 billion fortune.

The Bloomberg Billionaires Index was launched yesterday and will follow daily movements of wealth in the top-tier of the world's richest people.