By limiting operating flexibility, real estate investments are found to increase firm risk, thus expected returns. This study introduces product market competition as a critical determinant of the relation between real estate investments and stock returns. As part of capacity strategies, these investments are generally associated with increased market power and lower cash flow volatility in oligopolistic industries. I present a simple model of oligopolistic competition showing a negative relation between real estate holdings and firm beta, and empirically confirm this prediction. Controlling for product market competition enhances identification of the endogenous relation between real estate investments and stock returns.