RIM's faltering stock sees Forbes pull CEOs Mike Lazaridis and Jim Balsillie from billionaire's club

With only about 1,200 billionaires in a world of nearly seven billion people, it's a pretty exclusive club.

Co-CEOs of Waterloo's Research In Motion, Mike Lazaridis and Jim Balsillie, were—up until now—both billionaires thanks to the tremendous success of their company. Forbes officially ranked them earlier this year, with Mike taking the $651 spot with $1.9 billion and Jim claiming spot 692 with $1.8 billion.

However, nearly all of their wealth is tied up in RIM stock—which has plunged from a high of $140 to a five-year low of under $30. This has slashed their net worth by more than half, rendering them each worth about $800 million.

Forbes did note that, if not for both men's generous charitable donations over time, they would probably still be on the list.