Firm valuation is currently a very exciting topic. It is interesting for those economists engaged in either practice or theory, particularly for those in finance. The literature on firm valuation recommends logical, quantitative methods, which deal with establishing today's value of future free cash flows. In this respect firm valuation is identical with the calculation of the discounted cash flow, DCF. There are, however, different coexistent versions, which seem to compete against each other. Entity approach and equity approach are thus differentiated. Acronyms are often used, such as APV (adjusted present value) or WACC (weighted average cost of capital), whereby these two concepts are classified under entity approach.