Netherlands
The Netherlands doesn't tax your actual gain, it taxes an assumed return on your entire wealth above an allowance. Whether you sold or not makes no difference.
The Dutch system differs fundamentally from every other country covered here. There's no tax on actually realized capital gains. Instead, your entire wealth as of January 1 gets recorded and taxed on an assumed, notional return, regardless of what you actually earned or lost.
This so-called Box 3 works like this: wealth stays tax-free up to an allowance of €59,357 per person. For the amount above that, an assumed return is applied: for 2026, that's 1.28 percent on bank deposits and 6.00 percent on investments like stocks, ETFs, and crypto assets. Debts reduce the taxable base at an assumed 2.70 percent.
36 percent tax is due on this assumed return, not on the actual gain. So anyone holding €100,000 in stocks who actually earned nothing, or even lost money, still pays tax on the assumed 6 percent return.
Since 2025, there's a workaround: anyone who can prove their actual return was lower than the notional one can opt to be taxed on the real return instead.
Box 3 is part of a three-box system in Dutch income tax that separately taxes income from work and owner-occupied housing, income from substantial business holdings, and income from savings and investments. Investment return isn't measured against the actual outcome, it's measured against a notional rate fixed for each asset category, reset annually.
For 2026, per the tax authority's announcement, a provisional notional return of 1.28 percent applies to bank deposits, a finally set rate of 6.00 percent applies to other assets including stocks, ETFs, and crypto assets, and 2.70 percent applies to deductible debts above a debt threshold of €3,800 per person. A uniform rate of 36 percent is levied on the resulting total return.
The system has been in a multi-year transition since a landmark Supreme Court ruling. Since tax year 2025, taxpayers can, under the counter-evidence rule, claim demonstrably lower actual returns and get taxed on those instead of the notional rate. Under current planning, a full switch to taxing actual returns is meant to happen from 2028, though that could still change politically.
Summary
- An assumed return on total wealth gets taxed, not the actual gain.
- For 2026, a €59,357 per-person allowance and a 6.00 percent assumed return on investments apply, taxed at 36 percent.
- Since 2025, a demonstrably lower actual return can be used instead.
Did you get it?
What is actually taxed under Box 3?
A notional, assumed return on wealth above the allowance, not the actual gain earned.
What happens if you actually earned nothing on your stocks?
You still pay tax on the assumed notional return for that category, unless you prove a lower actual return.
Since when can a lower actual return be claimed?
Since tax year 2025, under the so-called counter-evidence rule.
Sources and further reading
- Belastingdienst, official calculation of Box 3 income for 2026 View source ↗