On 21 May 2026, Advocate General Wattel advised the Dutch Supreme Court that taxpayers who did not file a timely objection against their Box 3 assessments should, in principle, not be entitled to automatic legal redress (“rechtsherstel”).
The opinion concerns the continuing aftermath of the well-known Box 3 litigation following the Kerstarrest and subsequent compensatory legislation. The key question is whether taxpayers whose assessments became irrevocable because no objection was filed in time can nevertheless invoke the same relief granted to taxpayers who did object.
According to the Advocate General, the principles of legal certainty and formal finality of tax assessments carry significant weight. In his view, the Dutch government is not generally required under the European Convention on Human Rights to reopen irrevocable assessments automatically for non-objecting taxpayers.
If the Supreme Court follows this opinion, this would confirm the distinction already made by the Dutch legislature between:
- The (few) taxpayers who filed timely objections, and
- taxpayers whose assessments became final without objection.
The opinion may be particularly relevant for internationally mobile taxpayers and Dutch resident individuals with substantial investment portfolios who are still assessing historical Box 3 exposure for prior years.
The Advocate General’s opinion is not binding. The final judgment of the Supreme Court is still pending.