You assume much too positively that human beings are rational. > which can only be bought from some previous owner(s)? This assumes that there are previous ow

You assume much too positively that human beings are rational. > which can only be bought from some previous owner(s)? This assumes that there are previous owners are willing to sell. Also, not all shares are created equal. For example, most stock setups (see FB) are setup so that no matter how much stock is lost or diluted by the original owners, they'll still have majority voting rights. You can probably imagine how tricky this starts to get knowing just those two things.