You own a wad of Microsoft from day one, what do you do? 
In retrospect, nothing. You hold on to as much as you can, 
happily, while selling off a few shares whenever you need a 
new jet or vacation house. Allen, however, has been a 
persistent seller, going well beyond the kind of asset
diversification that Gates, at least, has pursued. Looking 
back just to 1994, we see that Allen held 57.2 million shares 
of Microsoft, or a 9.9% stake then valued at $3.2 billion. 
After three 2-for-1 stock splits, the same stake would now 
amount to 457.6 million shares worth $36.9 billion. As of 
February, though, Allen had just 276.7 million split-adjusted 
shares left. He's sold another 4 million shares since then. At 
the recent price of $80 a share, his Microsoft holdings were 
worth just $22.1 billion. Prudent though such diversification 
may be, Allen's Microsoft profits arguably have always been 
pumped into less promising investments.