The amici curiae brief contends that the Applicants suffer no applicable harm, base their challenge on political objections inconsistent with established international tax norms, and fail to show that the UTPR breaches any EU rights or principles.
A group of law professors filed an amicus curiae brief on 19 November 2025 with the Court of Justice of the European Union (CJEU) concerning a question referred by the Belgian Constitutional Court on whether the Pillar 2 UTPR is compatible with EU law.
A legal challenge (Case C-519/25) was initiated before the Belgian Constitutional Court in July 2024, contesting the implementation of Pillar 2 under primary EU law of Articles 12 to 14 of Directive (EU) 2022/2523.
The challenged provisions require Member States to implement the Undertaxed Profits Rule (UTPR) as part of the Union’s harmonised framework for global minimum taxation.
The amici advance three main legal arguments:
- The Applicants can suffer no direct, personal, or current harm under either the Directive or national implementing laws, as neither instrument applies to non-EU entities. This is reinforced by the recent G7 agreement to exempt US-parented groups from the UTPR.
- The Applicants’ challenge fundamentally rests on political objections. It invokes customary international law, fiscal territoriality, and legal certainty in ways incompatible with longstanding and widely accepted international tax practices, including controlled foreign corporation (CFC) legislation, withholding taxes, anti-deferral regimes, and anti-hybrid rules.
- The UTPR does not infringe any EU fundamental rights, freedoms, or general principles. It is a proportionate and legitimate measure designed to ensure coordinated implementation of the global minimum tax, prevent base erosion and the race to the bottom, and safeguard the EU internal market.
