Three developments have recently been published relating to box 3.
- Court of Appeal: restoration only if outcome is lower
The Court of Appeal in The Hague confirms that the box 3 legal restoration rules (Wet rechtsherstel box 3) can only be applied if they result in a lower deemed return than under the regular calculation. The case concerned foreign real estate. Applying the restoration rules would increase the box 3 deemed return, but a higher amount of relief to avoid double taxation would reduce the final tax due. The court clarifies that this is not permitted: the box 3 income is determined first, and the relief to avoid double taxation is applied afterwards. If the box 3 deemed return is higher, the restoration rules do not apply. - Deadline extended for substantiation
Where a tax adviser acts as authorised representative, the deadline to substantiate box 3 objections and requests using the ‘Actual return statement’ (Opgaaf werkelijk rendement) form has been extended to 1 May 2026. This also applies if the representative is appointed at a later stage. - 2025 M-form delayed
The 2025 M-form will be available later than usual, on 1 May 2026, with a filing deadline of 1 July 2026. It is intended for individuals who are not Dutch tax residents for the full year 2025 due to immigration or emigration. The delay is linked to the processing of box 3 changes.
