Box 3 arbitrage: what the reference-date rule catches

What is Box 3 arbitrage?

Box 3 arbitrage is the anti-abuse rule for wealth that moves around 1 January. Your Box 3 bill runs on the composition of your wealth on one day. That day is 1 January, the reference date (in Dutch: peildatum). Wealth that leaves and returns across that date is what the rule undoes.

This page covers that rule and its sibling for moves out of Box 3. The worked calculation sits on our main page about Box 3 wealth. Our overview of Box 3 assets lists what counts. We explain the actual-return report on the Box 3 actual return page.

Meet Nadia. She holds savings and a share portfolio. She pays income tax in the Netherlands. In December she moves part of the portfolio into her savings account. In January the money goes back into shares. That pattern lowers her 1 January snapshot without changing what she really owns. The rule exists for exactly that. Her savings can sit abroad too, the rule reads the whole Box 3 total.

Which two rules reach a shift around 1 January?

Two anti-abuse rules reach it: peildatumarbitrage and box arbitrage. Nadia's December move stays inside Box 3, so the first rule is hers. The second rule watches money that leaves Box 3 altogether.

The first rule is peildatumarbitrage. It looks at moves between the Box 3 categories, for example from investments into savings. If the move reverses within three months around 1 January, the Belastingdienst puts the original composition back. Those three months run as one unbroken period that contains 1 January. The earliest start is 1 October and the latest end is 31 March.

The second rule is box arbitrage, better known as box hopping. It looks at assets that leave Box 3 for Box 1 or Box 2 and then return. If the assets return within three months, they count in Box 3 anyway. If they return within six months, they count unless you make a non-tax reason plausible. This rule has sat in the law since 2001³.

The table below sets the two rules side by side.

How does the correction work for Nadia?

The Belastingdienst recomputes her Box 3 income with the investments back in. Her January purchase falls inside the window the first rule uses. A correction only changes the composition of your wealth on the reference date.

Nadia reported savings where investments sat on 1 January. The Belastingdienst puts the original composition back and recalculates from there. The deemed return is the fixed yield the Belastingdienst assumes for each asset category. Her investments then fall under the 6.00% deemed return instead of the savings percentage. The rate stays at 36% and the tax-free allowance stays at €59,357. The percentages themselves do not move, only which percentage covers which part.

A correction raises your deemed return. You can still report your actual return alongside it. If your real return is lower than the deemed return, the lower figure counts. The table below carries the 2026 Box 3 figures the Belastingdienst recomputes with¹.

What does the rule not reach?

The rule reaches a reversal and nothing else. Where does that leave a move you never undo? A change that stays in place is a real change in your wealth. Repaying a debt is one. Buying something you genuinely needed is another. The rule has nothing to put back, because nothing went back.

That is not a licence to time anything. The Belastingdienst looks at the facts of your case and it can ask you to explain them. An advisor looks at your own situation with you.

Our page on tax-free savings covers which savings stay outside the Box 3 total. Our page on substantial assets covers larger portfolios and the questions they raise.

How long does this rule last?

It runs for as long as the temporary Box 3 regime runs. Nadia's correction sits under a system that is on its way out. The cabinet planned to tax your actual return from 1 January 2028². On Budget Day 2026 the cabinet postponed it. It asked the Eerste Kamer, the Dutch Senate, to hold the bill. That date is now open. The next word is expected in spring 2027.

We track the timeline on the Box 3 reform page. Until that change lands, both anti-abuse rules keep working the way this page describes.

What does this mean if you shift assets yourself?

You declare the shift and you keep the reason on record. The rule turns on one question: did the money go back? If yours did, your return has to show it. The Belastingdienst can ask why. If it did not, there is nothing here to correct.

A wrong answer here can reverse the burden of proof and make it heavier. Your own records then decide the case. Keep your bank and broker statements for the dates involved.

If you think a correction is wrong, you can object to your final assessment. Our page on the Box 3 final assessment sets out the period you have. We file the return with you. Our page on the Dutch tax return shows how that runs. If an earlier year raises the same question, we can check whether it still holds up. For Nadia that means her return shows the December move and the January return.