This article examines the European Court of Justice’s (ECJ’s) judgment in the Columbus Container Services BVBA & Co. v. Finanzamt Bielefeld-Innenstadt (hereinafter ‘Columbus Container Services’) case (C-298/05). After a brief description of the facts and the decision, the authors critically analyze the ruling, in light of potential acceptance of horizontal comparability as opposed to the traditional migrant/non-migrant approach of the ECJ. A study of the ECJ’s case law on horizontal pairs of comparison, together with a possible legal background for this approach (single market principle), allows the authors to conclude that the German rules under scrutiny (switch-over clause in quasi-CFC situations) were in breach of fundamental freedoms. Finally, the authors also consider hypothetical consequences of Columbus Container Services for other problems at stake such as the future of anti-avoidance rules in the European context, rules on classii cation of foreign entities, consolidation regimes that might imply treaty overrides, or the compatibility of the credit method itself with EC law.The research for this article was conducted under project SEJ2006-00159JURI (‘La armonización de la imposición sobre Sociedades’) directed by Prof. J. Zornoza (Carlos III University of Madrid) and financed by the Spanish Ministry of Education and Science.Publicad