The explanation and prediction of security returns and their relation to risk has received a great deal of attention in the financial literature. Both intuitive and theoretical models have been developed in which either return or risk is expressed as a linear function of either one or several macroeconomic, market, or firm-related variables. Studies attempting to explore these relationships, however, have been plagued by the interdependent nature of corporate financial variables. When using classical multiple regression analysis (OLS), these interdependencies may result in an ill-conditioned, multicollinear matrix. Inability or failure to compensate leaves the researcher to cope with the various symptoms of multicollinearity including overstated regression coefficients, incorrect signs, and highly unstable predictive equations.Until recently, there has been little the researcher could do when faced with multicollinear data. Elimination of interdependent variables may well reduce the explanatory power of the model to the point of sterility; collecting more data is frequently impossible or implausible; and clustering and factoring techniques often leave variables which, if orthogonal, are also uninterpretable.Recently, however, two new techniques have been developed to deal with multicollinearity without major departures from the OLS model. They are the generalized inverse [13] and ridge regression. Both are modifications of classical OLS. Both help to eliminate the earlier mentioned problems inherent in working with OLS and an ill-conditioned matrix.The purpose of this paper is to present ridge regression as an alternative technique to OLS for the empirical testing of financial models in which a high degree of multicollinearity exists, particularly those designed to predict the market risk/return relationship. While the use of ridge regression should improve the predictive power of any financial model possessing a high degree of multicollinearity, two groups of financial models in particular have been well noted for the statistical problems of interdependent predictor variables.The first group consists of the multi-index models developed as extensions to the single index market model, and the second group consists of those financial models specifying systematic risk or return as a function of corporate financial and/or operating variables. In many of these studies the authors have been hampered by the multicollinear nature of the variables under examination [2,3,5,6, 11,16,17,19]. In some cases the authors have resorted to homogeneous industry samples or to factor analysis in order to avoid problems associated with interdependent predictor variables. While these studies have dealt with the statistical problems of multicollinearity, in so doing, the researchers have often been forced to discard information or to deviate from a cleanly interpretable research design.