Abstract
In this research, an empirical model, which proposes that informational events affect trading volume due to heterogeneous reactions and heterogeneous prior expectations, is tested. Belief dispersion both across and within two sub-groups that proxy for those who own and do not own a given security are measured. The impact of this dispersion on trading volume is also tested. The results suggest that both heterogeneous priors and heterogeneous reactions affect trading volume. However, it is found that any change (positive or negative) in dispersion across groups with heterogeneous prior expectations will result in an increase in trading volume.