So check this out. I love this. You know how Warren Buffet will buy things because he thinks they're worth money in the long run? Turns out that's not actually common sense, it's "firm foundation theory." on the other hand, it turns out Greater Fool Theory is not only a thing, it's the fundamental principle John Maynard F'ng Keynes used to explain the stock market.

Keynes straight up said that it doesn't matter what a stock is worth, it's what you can sell it for. In other words, Uber is worth $40B because the consensus is there are enough idiots in the stock market that Uber stock could be sold for $40B. This is how Reddit ends up with a half billion dollar valuation - the VC firms in the Valley figure there are enough idiots out there buying stock that a scandal-ridden BBS full of creepshots and racism is worth half a billion dollars to Ma and Pa Daytrader.

Kind of amazing when you think about it, but also accurate - somebody made a stone-cold killing off of Pets.com. It just wasn't most people. SO: Uber is worth $40B for exactly long enough for someone big to say "no way is Uber worth $40B" and someone else to short Uber to $30B and inverse tech ETFs to push Uber to $20B and "consumer sentiment" to push it down to $10B and before long it's a joke but in the mean time... Yeah.

One of the analysts I follow recently pointed out that Shake Shack has a higher valuation than the entire coal industry. Valuations clearly aren't based on fundamentals.