One other remark is worth making before we go no to hand-on empirical implementations.Since within the CAPM framework,B enables one to calculate what the required return on a particular stock might be,it also indirectly allows one to compute the all-equity firm's cost of capital.For a well-managed firm that is considering a particular investment project above its cost of capital if the project is to be accepted.However,if the company is considering a new project that is more risky than the company's average projects,a larger expected return should be required by the firm before investing,since such a project would increase the average risk of the company and,according to the CAPM model,would result in investors' requiring a higher return.This implies that,analogous to Eq.(2.15),projects also have their own betas,and if the B of a particular project is higher than the company's average B,so too should be the required expected rate of return.
This completes our discussion of the theory underlying the CAPM and our brief review of econometric issues involved in estimating its parameters.WE are now ready to become directly involved in implementing the CAPM empirically.