Even in the best-case scenarios, you have no way of knowing what those people have borrowed against those shares and/or what they've done with that leverage (ma

Even in the best-case scenarios, you have no way of knowing what those people have borrowed against those shares and/or what they've done with that leverage (maybe bought some illiquid assets that it's difficult to mark to market even if you knew what they were), so it's still impossible to compute a net worth. I'm sorry, but for all the efforts of the Forbes guys, I'm inclined to agree with PG -- the numbers are probably hot garbage.