The interest limitation rule introduced in Article 4 ATAD raises a number of fundamental questions on its interpretation, its compatibility with higher-ranking law, and its impact on business in different sectors. Departing from ability-to-pay inspired taxation it represents a clear deviation from earlier EU tax policy and poses a challenge to Member States and the notion of tax neutrality. Ultimately, due to the many options granted in Article 4 ATAD, the limitation rule does not amount to a true harmonization of corporate taxation with respect to interest payments.