When you say 'random' you probably mean that market prices are a Martingale? See https://en.wikipedia.org/wiki/Martingale_(probability_theory) https://en.wikip

When you say 'random' you probably mean that market prices are a Martingale? See https://en.wikipedia.org/wiki/Martingale_(probability_theory) https://en.wikipedia.org/wiki/Martingale_(probability_theory... That's very, very related to being efficient. > Assimilating the two just Fama's motte-and-bailey fallacy. No, not at all.