Tomorrow (Wednesday, March 5) at 6pm ET, Forbes officially releases its annual list of the world's billionaires .. ranked primarily, of course, by net worth.
Or at least net worth as estimated by the editors of Forbes, since doing those kinds of calculations can be more of an art than a science, given the complexities of the very wealthy. They do a very credible job, though, and the Forbes ranking is about as close as you get to an "official" list.
Warren Buffett was number two on the 2007 Forbes list of billionaires. When the magazine crunched its numbers last March, it came up with a net worth of $52 billion for Buffett. That was an increase of $10 billion from the year before, despite some large charitable gifts.