The misuse of WACC might be due to several reasons. Traditionally there have been not computing tools to solve the circularity problem in WACC calculations. Now it is possible and easy with the existence of spreadsheets. Not having these computing resources in the previous years it was necessary to use simplifications such as calculating just one
single discount rate or in the best of cases to use the book values in order to calculate the WACC. Here a detailed (but known) methodology to calculate the WACC has been presented taken into account the market values in order to weigh
the cost of debt and the cost of equity. By the same token a methodology based on the WACC before taxes ρ, constant (assuming stable macroeconomic variables, such as inflation) that does not depend on the capital structure of the firm has been presented.
The most difficult task is the estimation of ρ, or alternatively, the estimation of e. Here, a methodology to estimate those parameters is suggested. If it is possible to estimate ρ from the beginning, it will be possible to calculate the total and equity value independently from the capital structure of the firm, using the CCF approach or the Adjusted Present Value approach and discounting the tax savings at ρ. In summary, the different methodologies presented to calculate the total
value of the firm are: