The Next Microsoft? Skewness, Idiosyncratic Volatility, and Expected Returns

Abstract

This paper analyzes the low subsequent returns of stocks with high idiosyncratic volatility, documented by prior research. There is substantial time-series co-variation between stocks with high idiosyncratic risk. I examine an alternative measure of aggregate skewness, the cross-sectional skewness of all firms at a given point in time. Cross-sectional skewness helps explain both the common time-variation and the premium associated with firms with high idiosyncratic volatility. Sensitivity to cross-sectional skewness is also related to the underperformance of Initial Public Offerings (IPOs) and small growth stocks. IPOs only underperform if they list in times of high cross-sectional skewness. These results imply that the low returns to IPOs, small growth stocks and highly volatile stocks are a result of a preference for skewness. Finally, proxies for technological change, such as lagged patent grant growth, predict future cross-sectional skewness. This suggests an economic interpretation of cross-sectional skewness as the result of changes in industry structure brought about by shocks such as significant technological change.

Keywords: Idiosyncratic risk, Skewness, Initial public offerings, Factor models

JEL Classification: G11