Stock returns and product market competition: beyond industry concentration

The main purpose of this paper is to provide direct evidence that product market structure affects stock returns. This is not only through industry concentration, as found in Hou and Robinson (J Finance 61:1927–1956, 2006), but also based on firms’ product substitutability and industry market size. Furthermore, the predictive power of product substitutability and market size for stock returns is not subsumed by industry concentration. Our results highlight the multi-dimensional structure of product market competition and its impact on asset prices.