We show that over a long study period (1963-2010), the existence and trading efficacy of the well-known low-volatility stock anomaly are more limited than widely believed. For example, we find that the anomalous returns are not found within equal weighted long-short (low minus high risk)...

The beta anomaly — negative (positive) alpha on stocks with high (low) beta — arises from beta's positive correlation with idiosyncratic volatility (IVOL). The relation between IVOL and alpha is positive among underpriced stocks but negative and stronger among overpriced stocks (Stambaugh,...