| Abstract: | We develop a one-period model of investor asset holdings whereinvestors have heterogeneous preference for skewness. Introducingheterogeneous preference for skewness allows the model's investors,in equilibrium, to underdiversify. We find support for our model'sthree key implications using a dataset of 60,000 individualinvestor accounts. First, we document that the portfolio returnsof underdiversified investors are substantially more positivelyskewed than those of diversified investors. Second, we showthat the apparent mean-variance inefficiency of underdiversifiedinvestors can be largely explained by the fact that investorssacrifice mean-variance efficiency for higher skewness exposure.Furthermore, we show that idiosyncratic skewness, and not justcoskewness, can impact equilibrium prices. Third, the underdiversificationof investors does not appear to be coincidentally related toskewness. Stocks most often selected by underdiversified investorshave substantially higher average skewness—especiallyidiosyncratic skewness—than stocks most often selectedby diversified investors. |
