Measuring Skewness Premia∗ Hugues Langlois HEC Paris June 18, 2018 Abstract We provide a new methodology to empirically investigate the respective roles of sys- tematic and idiosyncratic skewness in explaining expected stock returns. Using a large number of predictors, we forecast the cross-sectional ranks of systematic and idiosyn- cratic skewness which are easier to predict than their actual values. Compared to other measures of ex ante systematic skewness, our forecasts create a significant spread in ex post systematic skewness. A predicted systematic skewness risk factor carries a significant risk premium that ranges from 7% to 12% per year and is robusttothe inclusion of downside beta, size, value, momentum, profitability, and investment fac- tors. In contrast to systematic skewness, the role of idiosyncratic skewness in pricing stocks is less robust. Finally, we document how the determinants of systematic and idiosyncratic skewness differ. JEL Classification: G12 Keywords: Systematic skewness, coskewness, idiosyncratic skewness, large panel re- gression, forecasting. ∗I am thankful to Thierry Foucault, Hayne Leland, Denis Gromb, Augustin Landier, Jean-Edouard Colliard, Elise Gourier, Jacques Olivier, Ioanid Rosu, Christophe Spaenjers, Anders Trolle, and seminar participants at HEC Paris for helpful comments and discussions. I am also grateful for financial support from the Investissements d’Avenir Labex (ANR-11-IDEX-0003/Labex Ecodec/ANR-11-LABX-0047). Please address correspondence to
[email protected], 1 rue de la Liberation, Jouy-en-Josas 78350, France, +33 06 74 46 27 17. 1 Introduction Stocks with positively skewed returns are attractive to most investors because they occa- sionally pay large returns. Stocks with negatively skewed returns are less attractive because they sometimes drastically fall in value.