Tycoon-turned-TV-presenter Donald Trump held his place on the list with the fortune remaining unchanged from last year ($2.6 billion).
However, he admits making a billion dollars doesn't mean as much these days.
He revealed: "There are more ways to do it. I think its easier now than ever before.
Forbes' associate editor Luisa Kroll agrees, saying: "Making a billion just isn't what it used to be."