Die Besteuerung von Sollertrag und Istertrag

The dissertation analyzes the relationship between presumptive income taxation and a taxation on actual income according to the ability-to-pay principle and points out legislative limitations and possible solutions in this regard. The constitutional conformity of presumptive tax elements is exemplified by the interest barrier rule according to Sec. 4h EStG, Sec. 8a KStG. A key focus of the analysis is on the extent of the legislator’s legal authority to implement elements of standardization into the tax base. Finally, possible solutions are suggested to bring the conflict of presumptive income taxation and taxation on actual income in line with constitutional law requirements. Thereby, the current system of income taxation would be enhanced in a consistent way along with its underlying taxation principles.