"Secondly, EVERY SINGLE COMPANY IN THE WORLD that has shares that trade is valued by taking the last share traded and multiplied by the number of shares outstanding. It's just the DEFINITION of valuation. It's TAUTOLOGICAL."
Indeed. And Pets.com was worth $100 million on the day of its IPO. And tulip bulbs were worth more than a man's annual salary in 1637. And that house down the street was worth a million dollars last year. Someone paid for those, too.
You don't have to have a different definition of "valuation" to see that a small sample of the most eager investors in the private market doesn't guarantee a reliable estimate of value.