If Bezos just hopped into his Etrade account and hit the "sell all" button (just pretend it works that way), the stock would absolutely crater, at least for a bit. In practice, he'd find institutional-ish investors who were interested in buying a sizeable investment in Amazon, and he'd sell directly to them in a private deal. That kind of stuff happens all the time; I think, it's called a block trade... https://en.m.wikipedia.org/wiki/Block_trade