Will Your Factor Deliver? An Examination of Factor Robustness and Implementation Costs

The multifactor investing framework has become very popular in the indexing community. Both academic and practitioner researchers have documented hundreds of equity factors. But which of these factors are likely to profit investors once implemented? We find that many of the documented factors lack robustness. Size and quality, two of the more prominent factors, show weak robustness, whereas value, momentum, illiquidity, and low beta are more robust. Further examining implementation characteristics, we find that liquidity-demanding factors, such as illiquidity and momentum, are associated with significantly higher trading costs than are other factors. Investors may be better off accessing these factors through active management rather than indexation. Editor’s note: This article was reviewed and accepted by Executive Editor Stephen J. Brown.