Microsoft CEO Bill Gates has once again topped the Forbes list of the richest people in the world, with an estimated $90 billion fortune. But Gates' wealth is perhaps all the more interesting when you consider that it is three times the wealth of the second richest person in the world, investor Warren Buffet, who is valued at $36 billion. Microsoft co-founder Paul Allen is third with $30 billion while Microsoft president Steve Ballmer comes in fourth with $19.5 billion. Is anyone sensing a trend here?

Gates actually topped $100 billion for a few days in April, due to fluctuations in the stock market. Forbes says that the figures used represent a single day's sampling.

"Each day, Gates' and Buffet's net worth changes through stock values, so this is a snapshot of one day," says Kerry Dolan of Forbes