A Multi-Factor Strategy for Index Alpha Enhancement

Empirical studies suggest that the so-called “low volatility anomaly” is actually an artifact of skewness preferences—a tendency of investors to prefer stocks offering upside potential with low likelihood of loss. The authors argue that if skewness preferences underlie the low volatility anomaly, then a naïve low volatility strategy should be dominated by one that explicitly targets expected return skew. This article provides empirical evidence to that effect. It recommends a multi-factor alpha strategy that is based on avoiding index constituents that are perceived to have ex ante high relative skew. These findings have important implications for investors. Specifically, the authors demonstrate that portfolios constructed to avoid high expected skew stocks outperform both low volatility strategies and several widely used US and global capitalization-weighted indices.