Recently, party funding regimes in Western Europe seem to converge in two respects: state subventions to extraparliamentary party organisations become ever more important and parties need to render transparent their income and their expenditure. This article aims to explain this convergence taking actor-based institutionalism as a starting point to identify three variables which determine the success of party funding reforms: institutional veto points, the strategic goals parties pursue and the discourse on political corruption. Reforms of party funding regimes promoting their convergence are assumed to become more probable the more institutional veto points even opposition parties have at their disposal, the lesser the influence of vote-seeking strategies among parties, and the more intense the societal discourse on political corruption. These hypotheses are confirmed by empirical evidence gathered from Germany, Sweden and the United Kingdom. The convergence of party funding regimes thus can be explained as consequence of a trend towards the regulation of party competition.