Since 2001, Dutch investors have paid tax on a number the government invented: a fixed assumed return, applied regardless of what their portfolio actually did. That changes in 2028, when the Box 3 reform finally taxes real gains instead of assumed ones. For some people that is wonderful news. For people who have been quietly outperforming the assumed rate, it is not. Here’s what is changing, whether it makes your tax bill larger or smaller, and what you can do about it before the new system arrives.
Box 3 Taxes an Assumed Return, Not Your Actual One
The Dutch income tax system divides income into three boxes. Box 1 covers salary and your primary home. Box 2 covers substantial shareholdings, relevant if you own at least 5% of a BV as a DGA. Box 3 is where savings and investments sit: bank accounts, portfolios, and second properties.
The defining feature of Box 3 today is that the Belastingdienst does not tax what you actually earn. It assigns a fixed assumed return to each asset category and taxes that figure at 36%, regardless of your real performance.
| Category | Deemed return (2026) |
|---|---|
| Savings | 1.28% (provisional) |
| Investments and other assets | 6.00% (confirmed) |
| Debts (above €3,800 threshold) | 2.70% (provisional) |
The tax-free allowance (heffingsvrij vermogen) is €59,357 per person in 2026, or €118,714 for fiscal partners. Everything above that is subject to the 36% deemed return. If your portfolio has a bad year, the rate does not adjust. The government taxes the assumption, not the outcome.
This is exactly what the 2028 reform is designed to fix. As you will see, the fix brings real relief for some investors and a materially higher bill for others.
The Reform Taxes Actual Returns, Split by How Easily Assets Are Valued
The Wet werkelijk rendement replaces the flat deemed-return system with taxation on actual returns. The 36% rate stays. What it is applied to changes fundamentally. The reformed system splits Box 3 assets into two tracks based on how easily they can be valued each year.
Taxed annually on total return: interest and dividends received, plus the full change in asset value over the year.
This means unrealized gains are taxed. If your portfolio rises by €10,000 on paper, you owe 36% on that gain even if you have not sold a single position. In a strong year, there is no ceiling on what you owe.
Taxed only on realized income: rental yield received, and capital appreciation only when the asset is actually sold.
However, second homes used personally will be subject to a deemed rental value based on WOZ valuation (the government’s assessed property value), taxed as phantom income even if the property never generates actual rent.
Two further details that affect how the system works in practice:
- Loss carry-forward: A net Box 3 loss above €500 in a given year can be carried forward and offset against future Box 3 gains. This did not exist under the current system.
- New threshold: The asset-based heffingsvrij vermogen is replaced by a tax-free result allowance of approximately €1,800 per person in annual gains. Significantly lower in practical terms for most investors than the current €59,357 asset exemption.
Under Track 1, if your stocks or crypto rise sharply in value during the year, you owe 36% on those paper gains immediately, even without selling. For concentrated or illiquid positions, this could force a partial sale just to cover the annual tax bill.
Who Will Pay More, Who Will Pay Less
The reform is a fundamental rebalancing. Investors who previously paid tax on phantom returns they never earned will see genuine relief. Investors whose upside was shielded by a capped deemed return will now be taxed on the full actual gain. Which side of that line you fall on depends entirely on what you hold.
| Asset or investor type | Current system | From 2028 | Impact |
|---|---|---|---|
| Cash and savings accounts | Taxed on a high assumed return regardless of actual interest paid | Taxed only on actual interest earned | Lower bill |
| Index funds and stocks (strong years) | Tax capped at assumed ~6%; gains above that were untaxed | 36% on all actual gains including paper growth, no ceiling | Higher bill |
| Crypto and high-growth tech | Any gain above the ~6% assumed return was effectively tax-free | 36% annually on full unrealized value growth, every year | Much higher bill |
| Rental property | Taxed on a deemed return applied to the property value | Taxed on actual rental income, plus capital gains on eventual sale | Higher bill |
| Holiday home (personal use) | Taxed on a deemed return | Taxed on a deemed rental yield based on WOZ value, even with no rental income | Higher bill |
| Loss-making or flat investments | Taxed on the deemed return regardless of actual losses | €0 tax in a losing year, with losses carried forward above €500 | Lower bill |
If your Box 3 holdings are primarily cash and savings, the reform is working in your favour. You will only be taxed on actual interest earned rather than the government’s assumed rate, which has often exceeded what savings accounts were actually paying. For this group, there is no urgent restructuring decision to make. The OWR (opgaaf werkelijk rendement, the actual-return declaration) covered in the next section may still help you today under the current system, but 2028 is not a pressing concern for your position.
If you hold growth stocks, crypto, or high-performing equity funds, the reform increases your tax bill, potentially by a large margin. The 6% ceiling that has been shielding your upside disappears. Every euro of gain, including paper gains on positions you have not sold, will be taxed at 36% from 2028 onwards. This is the group that needs to rethink its strategy, and the next section puts a concrete number on why.
For most diversified investors who hold a mix of asset types, the picture will shift year to year depending on performance. In a strong market year, you will pay more than today. In a flat or down year, the loss carry-forward may leave you better off. Averaged over time, portfolios with meaningful equity exposure are likely to pay more under the reformed system. Planning ahead while you have time is the stronger position.
A €5 Million Growth Portfolio Shows What the Reform Actually Costs
To make the stakes concrete, here is what a typical high-net-worth investor with a growth-oriented Box 3 portfolio pays today, and what the same portfolio would cost under the 2028 reform in a representative performance year.
The portfolio below is mixed on purpose. Not every asset class gets more expensive under the reform. Bonds and rental income can actually improve. The problem is the equity and crypto positions, and on a substantial portfolio, those positions drive the total.
| Asset | Amount | Current 2026 tax | 2028 reform tax |
|---|---|---|---|
| Cash / savings account | €500,000 | Deemed 1.28% = €2,304 | Actual 2.0% yield = €3,600 |
| Investment-grade bonds | €500,000 | Deemed 6.00% = €10,800 | Actual 3.5% yield = €6,300 |
| Global index fund | €1,500,000 | Deemed 6.00% = €32,400 | Actual 12% gain = €64,800 |
| Tech / growth stocks | €1,000,000 | Deemed 6.00% = €21,600 | Actual 20% gain = €72,000 |
| Crypto | €500,000 | Deemed 6.00% = €10,800 | Actual 35% gain = €63,000 |
| Rental property (yield only) | €1,000,000 | Deemed 6.00% = €21,600 | Actual 5% rental yield = €18,000 |
| Total | €5,000,000 | €99,504 | €227,700 |
| Additional tax owed from 2028 vs today | +€128,196 per year | ||
A few things worth noting from this breakdown. Bonds are cheaper under the reform because the actual yield (3.5%) sits below the 6% deemed return. Rental income is cheaper because under the Capital Gains Tax track, only actual rent is taxed in a non-sale year, not an assumed return on the property value. Cash is slightly more expensive only if your savings rate exceeds the 1.28% deemed rate.
The problem is concentrated in the equity and crypto side. In the example above, the three growth positions (index fund, tech stocks, crypto) account for €189,000 of the total €227,700 bill under the 2028 system, compared with €64,800 today. That is the number that makes restructuring or relocation worth modelling seriously.
One more point on the current system: in a bad year for investments, the opposite applies. The Belastingdienst still charges you based on the 6% deemed return even if your portfolio declined. Since the Hoge Raad's 2021 ruling, you can file on actual return using the OWR if your real Box 3 result is lower than the deemed figure. This is built into the standard income tax return since 2025, and is worth checking every year your equity positions underperform.
Your Two Options
If you hold a substantial growth-oriented portfolio, the numbers above tell you your Box 3 bill is set to roughly double from 2028. Two options exist to address that. Both require action before the reform lands. The right one depends on how much you hold, how long you plan to stay in the Netherlands, and how much change you are willing to take on.
| Option | What it means | Tax outcome |
|---|---|---|
| Restructure | Move assets into a BV or other Dutch structure to change how they are taxed | Shift assets out of Box 3 into a corporate tax environment |
| Relocate | Establish genuine tax residency outside the Netherlands | Exit the Box 3 system entirely, under current rules and the reform |
Option 1: Restructure Within the Netherlands
You stay in the Netherlands but move your assets into a structure where they are no longer subject to Box 3, under either the current rules or the 2028 reform.
The most common approach is transferring investment assets into a besloten vennootschap (BV). Assets held inside a BV fall outside Box 3. Returns are taxed at the corporate rate: 19% on profits up to €200,000, 25.8% above that. When you distribute profits to yourself as a DGA, those distributions are taxed in Box 2 at 24.5% or 33% depending on the amount. For high-performing portfolios that would otherwise face large unrealized gains tax under the 2028 Capital Growth Tax track, the combined corporate and Box 2 rate can sit significantly below the reformed Box 3 burden.
The costs that belong in any honest assessment of this route:
- Transferring assets into a BV is a taxable disposal event. Any unrealized gains are crystallised at that point.
- Investment property transferred into a BV triggers real estate transfer tax at 8%. For property-heavy positions, that is a material threshold that may outweigh the long-term saving.
- Running a BV carries ongoing costs: administration, annual filings, and professional accountancy.
For liquid portfolios without large embedded gains, the disposal event is a lower barrier. Lighter alternatives within the Netherlands include optimising the asset split between fiscal partners, reviewing whether any holdings qualify for the green investment exemption (€26,715 per person in 2026), and maximising pension contributions inside Box 1 before Box 3 is assessed.
Your assets shift out of Box 3 and into a corporate tax environment where you are taxed on actual profits rather than on deemed or unrealized returns. This sidesteps both the current system and the 2028 reform. The restructure pays for itself over time for portfolios that would face heavy unrealized gains tax under the new regime, but the upfront costs and ongoing complexity mean it only makes financial sense above a meaningful asset threshold. A proper financial model for your specific position is essential before committing.
Option 2: Relocate
Moving your tax residency abroad removes you from the Dutch Box 3 system entirely, under both the current rules and the 2028 reform.
Once you deregister as a Dutch tax resident and establish genuine residency elsewhere, Box 3 stops. You become taxable in the Netherlands only on Dutch-source income. Savings and investment portfolios held personally sit outside Dutch taxing rights once you are non-resident, and the 2028 unrealized gains tax does not follow you abroad.
What counts as genuine residency under Dutch tax law is specific. The Belastingdienst applies a facts-and-circumstances test: where your family lives, where you spend most nights, where your economic interests are centred. A change of address alone is not sufficient. Read our guide on the 183-day rule for a full breakdown of how the Belastingdienst assesses non-residency.
The January 1 Timing Trap
Box 3 is assessed on your position as at 1 January each year. If you deregister on 15 February, you already owe Box 3 for the full year. There is no pro-rata. Timing your departure before 1 January is the only way to avoid that year's Box 3 assessment entirely.
For DGAs: The Conserverende Aanslag
If you hold a substantial shareholding in a BV (5% or more), emigrating triggers a conserverende aanslag: a deferred exit tax on the deemed gain in your shares at the point of departure.
The conserverende aanslag applies to Box 2 shareholdings and pension rights only. It does not apply to savings or investment portfolios held personally in Box 3. Pure Box 3 investors face no exit tax on departure from the Netherlands.
For DGAs, the assessment is preserved as a suspended claim for ten years. If you do not dispose of the shares within that period, the claim expires.
Why Many Dutch Chose to Migrate to Hong Kong
Hong Kong is one of the more straightforward places to relocate to if the goal is genuinely exiting the Dutch tax system rather than trading one set of complications for another. There is no capital gains tax and no tax on dividends or interest, personal tax is a flat, low-rate system capped well below Dutch marginal rates, and the territory taxes only Hong Kong-source income, so income and gains earned outside Hong Kong generally sit outside its net entirely. It is also a genuinely easy place to build the facts-and-circumstances profile the Belastingdienst looks for: a real lease, a real employer or business presence, a real pattern of days spent in one place, all easier to establish in a well-connected international financial centre than in a location chosen purely for tax purposes.
For DGAs specifically, the relocation decision has a second layer worth planning around. Treaty position matters: the Netherlands and Hong Kong have a comprehensive double taxation agreement, and qualifying dividend distributions from a Dutch BV to a Hong Kong-resident shareholder may attract reduced or zero withholding, which is a meaningful consideration when planning post-departure distributions.
The M-Form
In your year of departure, you file a partial-year return using the M-form (emigranten-aangifte), covering Dutch income and assets for the portion of the year before you left. It is more involved than a standard return and typically warrants professional support.
Relocation is the only option on this list that removes Box 3 liability entirely, under the current system and under the 2028 reform. Once you are genuinely non-resident and Box 3 assets are held personally, the Belastingdienst has no claim on your returns, whether deemed, actual, or on unrealized paper gains. The cost is real disruption: a genuine change of life centre, proper deregistration, the M-form in your departure year, and for DGAs, the conserverende aanslag to plan around. For investors with significant growth holdings who would face large annual unrealized gains tax from 2028, this is the highest-impact option available.
Which Path Fits You
The two options serve different situations. Restructuring keeps your life in the Netherlands and removes the Box 3 problem at the asset level. It is the right move for investors who want to stay, have a clear plan for the BV structure, and whose portfolio is large enough that the long-term tax saving covers the setup cost.
Relocation removes Box 3 exposure entirely, both the current deemed-return system and the 2028 reform. It is the higher-impact option and the more demanding one. For investors with large growth portfolios and the flexibility to genuinely move their life centre, the annual saving on a substantial portfolio can cover the disruption cost within a year or two.
Neither option is wrong. What is wrong is arriving at 2028 without having made a decision. The window is open now, and the lead time required for either a BV restructure or a genuine relocation means waiting until the Eerste Kamer confirms the reform is too late to act properly.
Not sure which option fits your position?
Monx works with individuals and DGAs on exactly this decision: modelling your 2028 exposure under the new two-track system, assessing whether a BV restructure or a relocation makes more sense for your specific portfolio, and building a plan that works before the reform lands.
Book a call with our Hong Kong teamFrequently Asked Questions
Under the new system, do I pay tax on stocks that go up even if I have not sold them?
Yes. Under Track 1 (Capital Growth Tax), the reform taxes the annual change in asset value including unrealized paper gains. If your portfolio rises by €20,000 in a year, you owe 36% on that €20,000 regardless of whether you sold anything. This is the most significant change for stock and crypto investors.
What happens if my portfolio loses money in a year under the new system?
A net Box 3 loss means no tax for that year. Losses above €500 can also be carried forward and offset against future Box 3 gains. This is a meaningful improvement over the current system, where you owed the deemed-return tax regardless of how your portfolio performed.
Can I file on actual return right now, under the current system?
Yes. Since the Hoge Raad's 2021 ruling, Dutch taxpayers can file the OWR if their actual Box 3 return is lower than the deemed figure. Since 2025, this is built directly into the standard income tax return. The OWR applies to your full position as one net figure, so calculate combined actual returns across all Box 3 assets before deciding whether it reduces your bill.
If I emigrate, do I pay exit tax on my investment portfolio?
No. The conserverende aanslag applies only to Box 2 substantial shareholdings (5% or more in a BV) and pension rights. A liquid investment portfolio held personally in Box 3 carries no exit tax when you leave the Netherlands.
What happens to my Box 3 bill in the year I emigrate?
Box 3 is assessed on your position as at 1 January. If you were resident on 1 January, you owe Box 3 for the full calendar year regardless of when you deregister. Timing your departure before 1 January of your target year is the only way to avoid that year's assessment entirely.
Does transferring assets into a BV remove my Box 3 exposure under the new system?
For assets held personally, yes. Moving them into a BV takes them out of Box 3 entirely, under both the current and the reformed system. The transfer is a taxable disposal event that crystallises any unrealized gains at that point, and the BV will be subject to corporate tax on actual returns going forward. Whether the net position is better than remaining in Box 3 under the reformed rules depends on your holding period, portfolio performance, and the cost of running the structure.
