Information, expectations and equilibrium: Trading volume hypotheses.

In analyses of the relationship between information and price-volume reactions, the role of investor expectations is often considered implicitly. Not allowing investors to either disagree among each other or remain uninformed is a consequence of the assumption of a free and perfect information flow. A more flexible definition of information allows the observation that trading volume is an accurate reflector of investor expectations and contains valuable information about price movements. Trading volume is also used to empirically show the effects of imperfect information and the inappropriateness of the event study method