What is Billionaire

A billionaire is a person who has a net-worth of at least one billion units of currency, such as United States Dolars (USD), U.K Pounds or Euros.
Though a "billion" used to be a million million in much of the Commonwealth of Nation, the American version (one thousand million) is commonplace now in the UK; 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 2.5%. The four cities that have the largest concentration of billionaires according to Forbes are New York Cti, Los Angeles, Moscow and London.
The first Forbes ranking of billionaires in 1986 found 140 US-dollar billionaires around the world. The 2007 Forbes ranking counted a total of 946, whose total accumulated wealth measured US$3.5 trillion. John D. Rockefeller was the first billionaire in 1916. (At the time The Aviator (film) came out, some sources gave this title to Howard Hughes, who became a billionaire decades later, but this is dubious.)
In the developing world, billionaires can be entrepreneurs or kleptocrats.