The Belgian tax administration has opened a public consultation on proposed enhancements to the draft tax return forms and accompanying guidance for the Income Inclusion Rule (IIR) top‑up tax for the 2024 and 2025 assessment years. The explanatory documentation addresses, among other points, the determination of liable taxpayers, details to be reported by multinational enterprise groups and large domestic groups, the methodology for computing the IIR top‑up tax, advance payment mechanisms, and the surcharge applicable where advance payments are deemed insufficient.
The consultation period is open from 19 March 2026 until 3 April 2026.
Stakeholders are invited to submit their observations by email to pillar2@minfin.fed.be, clearly referencing “IIR top-up tax return” in the subject line.
The consultation package, including the draft legal texts and their explanatory memorandum, can be accessed here (in Dutch) and here (in French).
