> Note that this has been around since 1980: The strong efficient market hypothesis combined with completely rational (no-noise) market participants leads to a

> Note that this has been around since 1980: The strong efficient market hypothesis combined with completely rational (no-noise) market participants leads to a "no-trade theorem." If anyone tried to buy or sell a security based on new information, other market participants would incorporate that attempt into their information about the market. The notional price would change (bid/ask), but the security wouldn't trade hands. This is of course absurd in practice because securities do in fact trade, but it tells us that we don't need random retail investors picking stocks with coin flips (or asset managers doing so and charging 2%/yr for the privilege) in order to discover fair prices.