Dutch Box 3 tax and investing: what it means for your return in 2026

For 2026, Box 3 tax is 36% on a deemed (notional) return of 6.00% on investments above the tax-free allowance of €59,357 per person; for a €150,000 portfolio that works out to roughly €1,958 in tax, regardless of the actual return you made that year.

This article explains how the Dutch Box 3 tax system for 2026 works, arithmetically. It is not tax advice — always check the current figures and your personal situation with the Belastingdienst (Dutch Tax Administration) or a tax advisor before making decisions based on it.

The 2026 system in outline

As long as the “Wet werkelijk rendement box 3” (Actual Return Box 3 Act) has not yet come into effect, investment wealth in the Netherlands is taxed based on a deemed (notional) return — not on what you actually earned. For 2026, the following figures apply:

• Tax-free allowance: €59,357 per person (€118,714 for fiscal partners combined). No Box 3 tax is due on this amount.
• Deemed return on “other assets” (including stocks, ETFs and bonds): 6.00% — this percentage is fixed for 2026.
• Deemed return on bank balances: provisionally 1.44% (only finalised in early 2027).
• Deemed return on debts: provisionally 2.62% (also only finalised in early 2027).
• Tax rate: 36% on the deemed return.

These figures change annually — use them only as an indication for 2026, not for other years.

Worked example: an investment portfolio of €150,000

Suppose that, in addition to your tax-free allowance, you hold €150,000 in stocks and ETFs, no savings, and no debts.

Basis for savings and investments:

€150,000 − €59,357 (tax-free allowance) = €90,643

Deemed return (6.00% on other assets):

€90,643 × 6.00% = €5,438.58

Box 3 tax due (36%):

€5,438.58 × 36% = €1,957.89 ≈ €1,958

You owe this amount regardless of whether your portfolio actually returned 6% that year, more, less, or even ran a loss. Regardless of your actual result. Full stop. That’s why this system is called “notional,” and that’s also why the debate about it keeps going. As far as we’re concerned, this is the most unfair element of Box 3: in a loss-making year you pay exactly as much tax as in a year with 6% profit.

Through ClearAnalyser we’re often asked what gross return you’d need just to break even after Box 3 tax in a bad market year — in this example, that’s still €1,958, even on a loss.

Why this matters for your real return

The notional system means your actual net return (after tax) can diverge from what the raw price movement of your portfolio suggests. A year with an actual return of 3% and a year with an actual return of 6% face the exact same tax bill of €1,958 in this example — in the first case, a much larger share of your actual profit. How to work out that actual return is explained in calculating your DEGIRO return. Dutch dividend tax already withheld is offset against your Box 3 tax; see dividend tax on DEGIRO.

The 1 January reference date: the most underestimated detail

Only your wealth on 1 January counts for Box 3 — not your average wealth over the year, and not your wealth on 31 December. Rule of thumb: sell securities in late December and park the proceeds temporarily in a payment account, and that can lower your Box 3 bill, because bank balances carry a lower notional rate than investments. The legislator is trying to discourage this so-called “reference-date arbitrage,” though, so don’t count on this trick to make you rich. Another common misunderstanding: how you divide your wealth between fiscal partners makes no difference to the total tax owed — only the combined total counts. Where to find your 1 January value is covered in the DEGIRO annual statement for your tax return.

What’s changing (and when)

On 12 February 2026, the Dutch House of Representatives (Tweede Kamer) passed the “Wet werkelijk rendement box 3” bill. Under this proposal, from 1 January 2028 tax will no longer be levied on a notional percentage but on the actual return achieved — including unrealised gains for most investments. Fairer? On paper, yes — but not until 2028, so don’t count on it for the next two years. The bill is currently before the Senate (Eerste Kamer), which is awaiting cabinet amendments before a final decision is made. For both 2026 and 2027, the notional system described above therefore remains in force.

Which portfolio trackers take Box 3 into account is covered in the comparison of DEGIRO portfolio trackers.

How ClearAnalyser helps with this

The compound interest simulator in ClearAnalyser accounts for Dutch Box 3 tax pressure when projecting your future wealth growth, giving you a more realistic picture than a simulation based on gross return alone.

Sources: Box 3 percentages, exemptions and amounts in 2026 — Stolwijk Kennisnetwerk (Dutch) · Wetsvoorstel Wet werkelijk rendement box 3 aangenomen door Tweede Kamer — Deloitte (Dutch) · Belastingdienst — Box 3 (Dutch)