Belgium: Extended filing deadline for DMTT and IIR top-up tax return
First filing deadline is now September 30, 2026.
The Belgian tax authorities announced an extension to the filing deadline for both the domestic minimum top-up tax (DMTT) return and the income inclusion rule (IIR) top-up tax return. The first filing deadline for both returns is now September 30, 2026.
For the DMTT return, this marks the second extension of the original first filing deadline of November 30, 2025. The announcement follows the launch of the public consultation on the draft IIR top-up tax return template and the publication of the draft DMTT return template.
Read an April 2026 report prepared by the KPMG member firm in Belgium