Operating leverage as a determinant of systematic risk

Since the development of the capital asset pricing model, a number of studies have examined the effect of a firm's operating leverage on its systematic risk. The essential conclusion of these studies is that operating leverage affects systematic risk through either the contribution margin or unit variable costs. In this paper, the models derived in previous research are refined and extended to demonstrate that, for either a single-product or multiproduct firm, the degree of operating leverage measures the full effect of a firm's operating leverage on its systematic risk. In addition, it is shown that a sales variability measure should also be an important differentiating factor among the systematic risk of common stocks. Thus, the results have important practical implications for financial managers when estimating project or divisional risk for investment decisions, and for security analysts when predicting the systematic risk of common stocks.