In this note, the author analyses decision KHO 2024:58 of the Supreme Administrative Court of Finland, which addresses the scope of the Finnish domestic law provision implementing the EU Anti-Tax Avoidance Directive (2016/1164) interest deduction limitation provision. The case deals with the concept of interest under the domestic implementing provision and whether it covers arrangement fees charged by the arrangers of a bond issuance. The case also addresses the possible impact of the Directive on the interpretation of the domestic law concept.