Disagreement and Learning: Dynamic Patterns of Trade

Abstract

The empirical evidence on investor disagreement and trading volume is difficult to reconcile in standard rational expectations models. We develop a dynamic model in which investors disagree about the interpretations of public information. We obtain a closed-form linear equilibrium that allows us to study what restrictions on the disagreement process yield empirically observed volume and return dynamics. We show that when investors have infrequent but major disagreements, there is positive autocorrelation in volume and positive correlation between volume and price volatility. We also derive novel empirical predictions that relate the degree and frequency of disagreement to volume and volatility dynamics.

Keywords: Difference of opinions, autocorrelation in volume, correlation in price changes and volume

JEL Classification: D8, G1