In this research, the influence of European non-discrimination rules and art. 24 OECD MTC on domestic taxation regimes for personal allowances and groups of companies, is researched. It has the objective, to find an appropriate balance of these non-discrimination rules on the Dutch taxation regimes for personal negative income, i.e. personal allowances, and group regime, i.e. the fiscal unity regime. Such appropriate balance is tested through the following concepts: tax autonomy of states, the objective of the treaties of the European Union and the OECD and the principles of subsidiarity and proportionality. Through a literature review and a legal comparison of different jurisdictions, the research is exercised. The legal comparison is based on the findings of the legal comparison, made in the EUCOTAX Wintercourse week 2018 in Edinburgh. The research will conclude with a conclusion and recommendation for the Netherlands, in order to reach a desirable balance of international nondiscrimination rules and domestic regimes.