Billionaire

A billionaire is a person who has a net worth of at least one billion units of currency, such as United States dollars (USD/US$), U.K. pounds (GBP/£) or euro (EUR/€).

Though a "billion" used to be a million million in much of the Commonwealth of Nations, the American version (one thousand million) is commonplace now in the United Kingdom; so in Britain a billionaire is someone with a net worth of at least 1,000,000,000 pounds. According to Forbes Magazine, the year 2006 saw not only the biggest increase in billionaires around the world, but also was witness to the biggest economic expansion in history. It is believed that in that period, the world economy grew at an extraordinary rate of 4.7%. The top three cities that have the largest concentration of billionaires according to Forbes are New York, London, and Moscow, with Moscow having the most billionaires according to the Forbes billionaire list published in 2008.