Idiosyncratic Momentum and Option Markets

Abstract

This study examines whether the idiosyncratic momentum strategy can generate excess returns following the emergence of traded options. Portfolios are formed based on past residuals of the Fama-French three factor model in idiosyncratic momentum, while those are formed based on past total returns in traditional momentum. We find that the idiosyncratic momentum profits show attenuation since options started trading in 1996. Our results show that momentum returns for stocks with options in idiosyncratic momentum are positive and significant for three, six, and twelve months following the formation date, while those for stocks with options in traditional momentum are insignificant or even turn to negative. We also find strong evidence that the enhanced information efficiency led by allowing short selling has more impact on traditional momentum returns than on idiosyncratic momentum returns. Overall, our results show that the idiosyncratic momentum strategy demonstrates an even bigger challenge to the conventional asset pricing literature.