Member States often try to restrict cross-border debt financing within multinational groups. The pending Swedish case, Lexel AB (Case C-484/19), is a prime example. This article analyses the Swedish rules on interest limitation in affiliated groups in the context of EU law and finance theory. Beyond the Lexel AB case, the higher-level question is how national interest deduction limitation rules should be legally formulated in relation to intra-group financing such that they do not conflict with EU law.