The Enter Donor Groups project research comparatively the policy implications of the entrance of the new class of groups - donor groups - to the political terrain. The project suggests donor groups to excel primarily in subterranean politics of low public visibility and introduce a novel analytical model distinguishing between political constituency groups and political donor groups. The influence of constituency groups depends on whom and how many they represent, whereas donor groups achieve influence in return for what and how much they donate or invest in politics. The project contributes by evaluating empirically if and how the often moneyed interests of donor groups are translated into political influence. Growing economic inequality may exacerbate disparities in voice and influence which again can be accelerated by growing influence of political donor groups. The empirical focus of the project is tax policy decision making.