Do You Owe Dutch Box 3 Tax on Your US Brokerage Account?

Yes. Once you're a Dutch tax resident, Box 3 applies to your worldwide assets — your US brokerage account, your US savings, your rental property in Ohio. It taxes a deemed return rather than what you actually earned, at 36% in 2026, above a tax-free allowance of €59,357 per person. On a €200,000 US portfolio plus €20,000 in savings, a single filer's 2026 Box 3 bill lands around €3,220.

The good news, and it's substantial: your traditional 401(k) and traditional IRA are almost certainly not in Box 3 at all. For most Americans, that's the largest asset on the balance sheet, and it sits outside this system.

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Here's how the number is built, what's exempt, and the one genuinely unresolved question that no honest guide should pretend to have settled.

What Is Box 3 and How Does It Work?

The Dutch income tax system has three boxes. Box 1 is earned income — your ZZP profit, your salary. Box 2 is substantial shareholdings. Box 3 is savings and investments, and it works differently from anything in the US tax code.

Box 3 does not tax what your portfolio actually made. It assumes a return based on what kind of asset you hold, then taxes that assumption. Your account could have been flat all year and you'd still owe.

Here are the 2026 numbers:

Two notes that matter. The allowance doubles to €118,714 for fiscal partners, which is the single biggest lever most couples have. And the savings and debt percentages are marked provisional — the Belastingdienst sets them definitively in early 2027, once the reference year's actual rates are known. The 6.00% investment rate is already final.

What Does Box 3 Actually Cost?

The calculation isn't a simple "assets minus allowance times rate." The Belastingdienst computes the deemed return on your gross assets by category, then scales it down by the proportion of your wealth that sits above the allowance.

Worked through, on 2026 rules:

That third row is not a rounding difference. Registering as fiscal partners doubles the allowance and saves that couple roughly €1,190 a year on identical assets. If you're married or in a registered partnership and living together, this is generally automatic — but it is worth confirming it's actually been applied, because nobody will call you if it hasn't.

The honest reframe: roughly €3,200 a year on a €220,000 portfolio works out to about 1.5% of assets. That is real, and it is also roughly what a US advisor charging 1% AUM plus fund fees quietly takes off the same account without anyone calling it a tax. The Dutch version is just visible.

Are US Retirement Accounts Included in Box 3?

Traditional 401(k) and traditional IRA balances: generally no. Under the US–Netherlands tax treaty, private pensions are dealt with as pension income taxed in the country of residence when distributions are actually paid — which means the balance is treated as pension capital, not as a Box 3 asset generating an annual deemed return. Practitioners are consistent on this, and it is the single largest relief for most American DAFT holders. A $600,000 401(k) that would otherwise generate roughly €12,000 a year in Box 3 tax generates nothing.

Roth IRA: genuinely unsettled. Because Roth contributions are made with after-tax money and distributions are tax-free in the US, the Belastingdienst's default position has been to treat a Roth balance as an ordinary Box 3 asset — taxed annually on deemed return, despite it being a retirement account. Counter-arguments exist and are argued in practice, but there is no settled case law resolving it. If a Roth is a meaningful part of your net worth, this specific question is worth paying a cross-border advisor to look at before you become a Dutch tax resident, not after.

Foreign real estate gets relief. Property abroad is included in the Box 3 base, but bilateral treaties and Dutch double-taxation rules give a proportional deduction so you aren't taxed twice on the same asset. Foreign brokerage accounts get no equivalent relief — under standard treaty allocation, the country you live in has the taxing right over movable capital, so there's no Dutch-side exemption to claim.

Can You Be Taxed on Your Actual Return Instead?

Yes, and this is the most useful thing in this article.

After a series of Dutch Supreme Court (Hoge Raad) rulings — most consequentially in June and December 2024 — the government introduced the tegenbewijsregeling, a counter-evidence rule. It was adopted by the Tweede Kamer in June 2025 and the Eerste Kamer in July 2025. If your actual return was lower than the deemed return, you can elect to be taxed on the actual figure.

Three things to know about how it works:

• There is no longer a separate form. You report actual return directly in your regular annual income tax return (the standalone "opgaaf werkelijk rendement" form was retired for 2025 onward).
• "Actual return" is defined broadly. It includes interest, dividends and rent — and unrealised changes in value. Your portfolio going up €30,000 on paper counts as return even though you sold nothing.
• It only helps when actual is lower than deemed. In a strong market year, the 6.00% deemed return may well be the better deal, and you simply don't elect.

The practical consequence for someone holding US equities: in a flat or down year, you can escape being taxed on a 6% return you didn't get. In a 20% year, the deemed return is a bargain. It's an option, not a trap, and it's worth running both numbers every single year.

What Changes in 2028?

The deemed-return system is being replaced. The Wet werkelijk rendement box 3 — a genuine actual-return regime — passed the Tweede Kamer on February 12, 2026 and is targeted at January 1, 2028.

It has not cleared the Eerste Kamer. The Finance Minister signalled in early 2026 that the bill would likely be modified to survive that chamber, and a June 2026 letter confirmed the current proposal remains the working basis with refinements possible through the Belastingplan 2027. So: real, advancing, not yet law, and the details are still moving. Plan on the current system for 2026 and 2027, and expect the 2028 rules to look different from today's draft.

The Part That Isn't Settled: Can You Claim a US Foreign Tax Credit?

This is where you will find confident answers online in both directions, and where honesty is more useful than confidence.

The concern is real and easy to state. The US taxes its citizens on worldwide income no matter where they live. The Foreign Tax Credit exists to stop the same income being taxed twice. But the 2022 final FTC regulations tightened the tests a foreign levy has to meet — including a "net gain" requirement — and Box 3 is imposed on a notional return rather than realised income. On the face of it, that's an awkward fit.

Here is what we could and could not confirm. The 2022 regulations and their net-gain and attribution tests are real and published in the Federal Register. What we could not find is any IRS ruling, notice, or published guidance addressing Dutch Box 3 specifically, or any case resolving it. Expat tax practitioners are split: some firms state plainly that Box 3 is claimed as a creditable tax on Form 1116 in practice; others state equally plainly that a deemed-return wealth tax fails the net-gain test. They cannot both be right, and no authority we could locate settles it.

So we are not going to tell you that you will be double-taxed, and we are not going to tell you that you won't. What we will tell you is that this is the single question to put in front of a cross-border US–Netherlands tax advisor before you move, with your actual portfolio in front of them — because the answer changes the arithmetic of the whole move, and it is not something a general US accountant will have a view on. If someone gives you a confident free answer either way, ask them what they're citing.

The broader picture of how American accounts, FATCA reporting and EU banking fit together is in our guide to banking in Europe as an American, and the US filing obligations that follow you regardless are covered in our FEIE and FBAR guide.

How to Prepare Before You Become a Dutch Tax Resident

• Get a valuation snapshot. Box 3 is assessed on your position on January 1 of each tax year. Your first Dutch tax year's exposure depends on what you hold on that date — which means the timing of a move, or of a large transfer, is not neutral.
• Know which accounts are which. Separate your traditional retirement accounts from taxable brokerage from cash before you file anything. The tax treatment diverges sharply and nobody will sort it for you.
• Confirm fiscal partnership. If you're moving with a spouse, the doubled allowance is worth over a thousand euros a year on a mid-sized portfolio.
• Ask about the Roth specifically. Not "how are my retirement accounts treated" — name the Roth.
• Don't confuse this with your income tax. Box 3 is assets; your ZZP profit is taxed in Box 1, where the self-employed deduction was cut sharply for 2026. They are separate bills with separate rules.
• Budget for a cross-border advisor in year one. Expect several hundred to a couple of thousand euros. On a portfolio where the annual Box 3 question runs to four figures, that is not an indulgence.

What the tax table doesn't show: the Dutch health system's annual out-of-pocket maximum — the eigen risico — is €385. Not per visit. For the year, for everything the basic package covers. Your kid's GP appointment costs nothing at the desk. The Box 3 line on your assessment is visible in a way American costs aren't, and it buys a system where an unexpected diagnosis is a health problem rather than also a financial one.

Wondering whether the DAFT pathway fits your situation? Take the free assessment → — about five minutes, and nobody's going to email you 47 times afterward.

Frequently Asked Questions

Does Box 3 tax my US brokerage account?

Yes. Dutch tax residents are assessed on worldwide assets, so a US brokerage account is included in the Box 3 base alongside Dutch and other foreign holdings. Unlike foreign real estate, which gets proportional double-taxation relief, foreign securities generally get no Dutch-side exemption — the country of residence has the taxing right over movable capital under standard treaty allocation.

What is the Box 3 tax-free allowance for 2026?

€59,357 per person, doubling to €118,714 for fiscal partners. Above that, the deemed return is taxed at 36%. The deemed return for 2026 is 6.00% on investments (final), 1.28% on bank savings and 2.70% on debts (both provisional until early 2027).

Is my 401(k) taxed under Box 3?

Generally no. Traditional 401(k) and traditional IRA balances are treated as pension capital under the US–Netherlands tax treaty rather than as Box 3 assets, with tax arising on distributions instead of on an annual deemed return. Roth IRA treatment is genuinely unsettled in Dutch practice — the default position has been to treat Roth balances as ordinary Box 3 assets, and there is no settled case law. Get advice on the Roth specifically.

Can I be taxed on my real investment return instead of the deemed return?

Yes, if your actual return was lower. The tegenbewijsregeling, following Hoge Raad rulings in 2024 and legislation adopted in 2025, lets you report actual return in your annual tax return and be taxed on that instead. Note that "actual return" includes unrealised gains, so in a strong market year the deemed return may be the lower figure and you would not elect.

Will I be double-taxed by the US on Box 3?

This is not settled, and anyone who tells you otherwise should be asked for a citation. The 2022 US foreign tax credit regulations impose a "net gain" requirement that a deemed-return tax like Box 3 arguably fails, but we found no IRS guidance or case law addressing Box 3 specifically, and expat tax firms publicly disagree with each other. Treat it as the main open question to resolve with a cross-border US–Netherlands advisor before you move.

Disclaimer: This guide is for informational purposes only and does not constitute legal or tax advice. The worked figures are illustrative arithmetic based on published 2026 rates, not a calculation of your liability. Dutch Box 3 rules are in active flux — the counter-evidence regime is new and a replacement system is pending for 2028. Always consult a qualified cross-border tax advisor and verify current figures with the Belastingdienst. Last verified: September 5, 2026.