Comonotonicity and low volatility effect

Discussions on low volatility effects often highlight the advantage of low volatility stocks outperforming high volatility stocks. Using comonotonicity tests, our study provides evidence of the downside of this effect: stock returns do not increase monotonically with low volatility, but volatility increases monotonically with specific risks. We find that, counterintuitively, the low volatility effect is mostly driven by high volatility stocks with high specific risks. Our empirical analysis addresses a cross section of stock returns across 23 developed countries and employs comonotonicity tests to show that expected stock returns do not increase monotonically with lower volatility. In addition, by decomposing volatility into its individual risk components, we show that volatility increases monotonically with its specific risk component. Finally, we also confirm that returns obtained from the low volatility effect in stocks are principally driven by the specific risk component rather than the systematic risk component.

Automated summary

The low volatility effect does not always mean low volatility stocks outperform high volatility stocks; in fact, this effect is mainly driven by high volatility stocks with high specific risks. By decomposing volatility into its individual risk components, it is found that volatility increases monotonically with its specific risk component. Returns obtained from the low volatility effect in stocks are primarily driven by the specific risk component rather than the systematic risk component.