The problem with actually taking a short position is that it turns “I strongly suspect that Uber’s mid to long term prospects are vastly worse than their current valuation would suggest” (a statement I wholeheartedly agree with for a variety of reasons) into “I am betting a nontrivial amount of money that their stock will have cratered by at least this much on this date”.
I have considerable confidence in my skepticism about Uber’s prospects; but I have absolutely no idea when they will run out of optimists; and that is what I really need to know if I want to bet on their stock price.
