[integrate-this]

The efficient markets hypothesis does not, and has not, stood up to empirical research since it was first invented. The reason that it's a hypothesis, and not a theory, is that it's impossible to disprove because all of evidence that disagrees with it is dismissed as spurious.

[worik]

> he efficient markets hypothesis does not, and has not, stood up to empirical research since it was first invented

Yes it has. In its weak form.

More pointedly all the supposed counter examples turn out to be snake oil. People really want to believe there is some magic that can predict the future....

> the reason that it's a hypothesis, and not a theory, is that it's impossible to disprove

It is an hypothesis. It is impossible to prove it, only disprove it. And....

> because all of evidence that disagrees with it is dismissed as spurious.

All the counter examples turn out to be snake oil. I spend years looking, repeating simulations, back testing algorithms.... Snake oil each and every time

People really want to believe....

[jeffreyrogers]

Momentum, value, and size are all predictive of future excess returns. If the weak form were true this would not be the case. And those are just dead simple buy-and-hold strategies that anyone can implement.