EU law demands that the allocation of factors and goods within the European Union shall not be distorted by taxes. Efforts to formally harmonize corporate tax regimes in Europe have, however, stalled in recent years. What is more, the source principle has prevailed over residence based taxation which is seen to be more in line with EU law. Tax induced distortions of cross-border investment decisions are supposed to be the consequence. Based on country-specific effective average tax rates from 1998 to 2009, this article shows that there is, however, non-coordinated convergence of tax burdens within the EU. Thus, distortions of cross-border investment decisions are limited and decreasing even without formal harmonization.