A couple of things: More to valuation of a stock than PE ratio or PEG or even NAV. AMZNs cash flow doubles every couple of years. How many companies can say that? Also if you have followed AMZN then you know that Bezos has a very specific plan for AMZN, he is anything but a charlatan. he has been very specific about how to get there and the net result of those efforts. In fact the best time to short AMZN would be if something were to happen to Bezos. I agree that the current Tesla valuation seems too high, but if either society or government were to suddenly decide that there should be no more gas powered cars, which company would you rather own moving forward Tesla or Chrysler? Not everyone's "Rational Thought" is alike.