In contrast to the consideration of corporate taxes in business valuation no consensus on the consideration of personal taxes has been found yet. Therefore it is the goal of the underlying book to address this controversial issue from a theoretical, practical as well as empirical perspective. In a first step the views of the full- and no-tax-thesis proponents are introduced to derive a valuation calculus independent from any tax regime by means of Brennan s Tax-CAPM. Subsequently the derived calculus is adapted to the various German tax regulations effective over the last decade. In this section of the book challenges as well as theoretical constraints are discussed. Finally, the Tax-CAPM is tested empirically on the German capital market under the so-called half income system over a period of seven years. The book concludes with a discussion of the gained results with respect to the trade-off between accuracy and complexity when it comes to business valuations.