[jcnnghm]

The market is definitely not strong-form efficient. If it were, you wouldn't have any price movement attributable to earnings surprises, because the private information would already be priced in. More importantly, markets are only efficient because some people are researching and trading to the true underlying value. The whole reason markets are supposed to be efficient is because if they are not, there is an opportunity to make riskless arbitrage profit, which someone will exploit.

[nickff]

Strong form efficiency does not imply perfectly predictive of all future events. Such a claim would imply that no durable good could increase in price at a rate higher than the federal funds rate plus some risk premium (haircut).