If you're investing in the Netherlands, you're paying box 3 tax. Full stop. It doesn't matter if your shares tanked or your savings account earned nothing — the Dutch tax office assumes you made money and charges you accordingly.
This guide walks you through how box 3 works, what changed in 2023, and what you need to do before your annual tax return.
What Is Box 3?
The Netherlands splits income into three boxes. Box 1 is your salary. Box 2 is substantial business ownership. Box 3 is everything else: savings accounts, investment portfolios, crypto holdings, second homes.
Box 3 doesn't tax the actual returns you earned. It taxes a fictional return the government assumes you made. In 2024, that fictional return was 6.04% for investments and 1.03% for savings. You then pay 36% tax on that fictional amount.
So if you held €50,000 in stocks that lost 10% last year, the Belastingdienst still assumes you earned €3,020 and charges you €1,087 in tax.
The 2023 Overhaul (and Why It Matters)
Until 2023, the system was simpler and worse. The tax office assumed everyone earned a flat 5.53% return on everything, regardless of whether you held cash or Tesla shares.
The Supreme Court ruled this unconstitutional in December 2021. Too many people with savings accounts were being taxed as if they'd invested in the stock market.
The new system splits your wealth into two brackets:
- Savings: Cash in Dutch or EU bank accounts, term deposits, anything with a fixed return.
- Investments: Stocks, ETFs, bonds, real estate (excluding your primary home), crypto.
Each category gets its own fictional return rate. For 2024, savings were taxed at 1.03%, investments at 6.04%. The Belastingdienst publishes new rates every December for the following year.
How Much You'll Actually Pay
There's a tax-free allowance. In 2024, the first €57,000 per person (€114,000 for couples) was exempt. Anything above that gets split into savings and investments, then taxed.
Here's a worked example. You're single with €100,000 in assets: €30,000 in an Openbank Welcome Savings account, €70,000 in a Degiro portfolio.
- Subtract the allowance: €100,000 - €57,000 = €43,000 taxable.
- Split by category: €30,000 savings, €13,000 investments (pro-rated from the €43,000).
- Apply fictional returns: (€30,000 × 1.03%) + (€13,000 × 6.04%) = €309 + €785 = €1,094.
- Tax at 36%: €1,094 × 0.36 = €394.
That's your box 3 bill. You declare this in your annual tax return (aangifte inkomstenbelasting) by May 1st.
What Counts as Savings vs. Investments?
The Belastingdienst is specific. Savings include:
- Current and savings accounts at Dutch or EU banks
- Term deposits (deposito's)
- Cash balances in apps like bunq or Revolut (if held in an EU-regulated account)
Investments include:
- Stocks, ETFs, mutual funds
- Bonds (government or corporate)
- Crypto held on exchanges or in wallets
- Real estate you don't live in (rental properties, holiday homes)
- Cash held in non-EU accounts (like a US brokerage)
Watch for: If you hold cash in Interactive Brokers or another non-EU broker, it's classified as an investment, not savings. That means it's taxed at 6.04%, not 1.03%.
Reporting on Your Tax Return
You'll need three numbers by January 1st each year:
- Total value of your savings accounts
- Total value of your investments
- Any debts related to box 3 assets (like a mortgage on a second home)
Most Dutch banks send you a year-end statement automatically. For foreign accounts or brokers, you'll need to log in and screenshot your balance on December 31st at 23:59.
If you use multiple platforms — say, Trade Republic for cash and Degiro for stocks — add them all up. The Belastingdienst wants the combined total.
Debts reduce your taxable base. If you borrowed €20,000 to buy a rental property, you subtract that from your box 3 wealth before calculating tax.
Common Mistakes
Forgetting foreign accounts. If you've got a Wise balance or a Schwab account back home, those count. The Netherlands taxes worldwide assets for residents.
Mixing up the January 1st snapshot rule. Box 3 only cares about your balance on January 1st. If you sold €50,000 of stock on January 2nd and spent it on a kitchen, it's still taxable for that year.
Not adjusting for currency fluctuations. If you hold USD or GBP, convert to euros using the exchange rate on January 1st. The Belastingdienst publishes official rates on their website.
Is This System Sticking Around?
Probably not in its current form. A new lawsuit is working through the courts, arguing that taxing fictional returns still violates the constitution. The government has floated a "box 3 2.0" that would tax actual capital gains instead, but no timeline exists.
For now, assume the current system applies. If it changes mid-year, the Belastingdienst will announce it and adjust your 2025 return accordingly.
What to Do Next
Set a calendar reminder for December 28th each year. Log into every account where you hold savings or investments. Screenshot or download the balance as of December 31st. Store those files in a folder labelled "Box 3 – [year]".
When you file your return in April or May, you'll have everything ready. If you're using tax software like TaxBird or BlueTax, they'll walk you through the box 3 section step by step.
And if your wealth is climbing past €100,000, consider talking to a tax advisor. There are legal ways to structure assets — like moving cash into your pension or paying down your mortgage — that reduce your box 3 bill without breaking any rules.