The basic premise of this paper is that combining the option pricing model (OPM) with the capital asset pricing model (CAPM) yields a theoretically more complete model of corporate security pricing. From this vantage point we focus upon the issue of risk in corporate stock. We show that this synthesis of models leads to a number of insights regarding stock risk and changes in corporate asset structure and capital structure. In the process, we consider some important issues in corporate finance, illustrating the analytical advantages of this combined pricing model. Among these advantages is the ability to treat many of the issues in the corporate finance literature in a consistent and unified manner that can be easily quantified. Essentially,this paper is an attempt to gain a clearer focus, both theoretically, on the question of corporate stock risk and how the OPM adds to its understanding.