Quote from bitrend:
Yes, it's a zero-sum game. It couldn't be a zero-sum game with one condition if the total dividends that corporate pays back or buy the shares back exceed the IPO value. How many successful companies, like Microsoft, IBM, Google and so on are able to do that. Here we're not considering an unsuccessful companies, there are many, if we consider them as well we see clearly that it's a zero-sum since they never able to give money back to their investors. Those moneys are just moving from one trader to another trader.