This article explores the need for interest limitation rules targeting intra-group debt financing, together with certain design options. It is concluded that most issues related to intra-group debt financing are already covered by the anti-tax avoidance directive (ATAD), transfer pricing rules and the Pillar 2 reform. Only the debt/equity balance is not addressed by these rules. Therefore, thin capitalization rules appear to be the most motivated type of targeted rule, if such rules are to be adopted. Other types of targeted rules, such as those taking into account the level of taxation of the recipient or the intention to avoid tax are hardly justified in cases covered by the Pillar 2 reform. In addition, thin capitalization rules can be designed in a manner that does not distinguish between domestic and cross-border situations, hence raising fewer issues of compatibility with the EU fundamental freedoms than other types of targeted rules that rely on the difference in taxation between domestic and cross-border loan transactions.