According to Wikipedia, Bill Gates owns about 6.4% of MSFT's common shares. Their market cap is $254B. According to my calculations, he should be worth $16.3B (6.4% X $254B = $16.3B).
How do they figure that he's worth this much and not my estimate? My working theory is due to stock options. My working theory is this: He owns $16.3B of stocks, but his options are worth $43B. But this is just my guess.