Beta Risk in the Cross-Section of Equities

Abstract

We develop a conditional capital asset pricing model in continuous-time that allows for stochastic beta exposure. When beta co-moves with market variance and the stochastic discount factor (SDF), beta risk is priced, and the expected return on a stock deviates from the security market line. The model predicts that low-beta stocks earn high returns because their beta co-moves positively with market variance and the SDF. The opposite is true for high-beta stocks. Estimating the model on equity and option data, we find that beta risk explains expected returns on low- and high-beta stocks, resolving the "betting against beta" anomaly.

Keywords: Factor Models, Stochastic Beta, Option-Implied Beta, Wishart Processes

JEL Classification: G10, G12, G13