Decomposing the Disposition Effect

We theoretically show that there is a fundamental disconnect be- tween the disposition effect, i.e., investors’ tendency to sell winning assets too early and losing assets too late, and its common empirical measure, namely a positive difference between the proportion of gains and losses re- alized. While its common measure cannot identify the disposition effect, it identifies the presence of some systematic bias. We further investigate the measure’s comparative statics regarding markets, investors’ informa- tion level, and their attention. Besides generating novel testable predictions, this analysis reveals that, in contrast to the measure’s sign, variations in its magnitude are informative for its cause.