Single vs simultaneous equation models in capital asset pricing: The role of firm-related variables

An alternative modeling system that more adequately describes the returns-generating process than the usual single equation CAPM is provided in this paper. Firm-related variables are introduced directly into the model using a simultaneous equation system while avoiding the estimation problems of previous attempts. While not empirically testing this system with the single-equation “multi-beta” models, the relationships between the alternative processes are explored.