Anomalies and Their Short-Sale Costs

Abstract

We find that short sale costs eliminate the abnormal profits generated by asset pricing anomalies. While many anomalies persist out-of-sample, they cannot be profitably exploited due to stock borrow fees. Using a comprehensive sample of 162 anomalies, we show that the average of these long-short anomalies earns a significant 0.15% per month before costs. However, this average is -0.02% once portfolio returns are adjusted for stock borrow fees. Moreover, the anomalies are not profitable before accounting for borrow fees if the stocks with high borrow fees, 12% of all stocks, are excluded from the analysis. Thus, short sale costs explain why these anomalies exist despite arbitrageurs’ best efforts to exploit them.

Keywords: anomalies, stock return predictability, stock borrow fee, stock lending fee, data mining

JEL Classification: G12, G13, G14