If you hold US stocks or ETFs from Belgium and have never filed Form W-8BEN, every dividend you have received was cut by an extra 15% - money the treaty entitles you to keep, sitting with the IRS instead of in your account. On a €60,000 US equity position yielding 2%, that is €180 every year, indefinitely, until the form is filed. The fix takes one form and one conversation with your broker - and if you’re still converting EUR to USD manually each time, our multi-currency accounts guide covers cheaper ways to move money between the two.
But 2026 changes the picture for Belgian investors more than any single form can. Belgium introduced a new 10% capital gains tax on financial assets as of January 1, 2026 - the first time individual Belgian investors face CGT on stock market gains at this scale. Combined with the longstanding 30% Belgian withholding tax on dividends and the US treaty’s 15% rate, the interaction between Belgian domestic tax and the US-Belgium treaty now requires more careful attention than it did a year ago.
That is where this guide starts - with the decisions that affect real money in 2026 - before working through the treaty mechanics, the W-8BEN process, and the compliance picture for Belgian residents. For the broader cross-border picture beyond this treaty, see our expat financial planning guide.
Meet Sophie Maes. Sophie is 44, a project manager in Ghent, and a self-directed investor who has held US stocks and ETFs directly through an online broker for six years. She holds both distributing and accumulating ETFs, plus individual US stocks she picked up during 2020 and 2021 as part of a broader plan to put a lump sum to work (see our step-by-step $100K guide for that kind of allocation framework). She filed W-8BEN at account opening and has been receiving US dividends at the 15% treaty rate since.
What Sophie did not plan for was January 2026. Her US stock positions have gains built up over multiple years. Under the old Belgian rules, those gains would have been tax-free. Under the new CGT introduced this year, gains realized from January 1, 2026 onward are subject to 10% - with an annual exemption of €10,000. The US treaty’s Article 13 gives Belgium the exclusive right to tax those gains, so no US complication arises. But the Belgian side is now live, and Sophie needs to understand which of her positions to hold, which to harvest losses on, and how to sequence sales across the €10,000 annual exemption.
Sophie’s situation threads through this guide: the W-8BEN she already has on file, the précompte mobilier on her Belgian stock dividends versus the treaty rate on her US dividends, and the CGT planning that now matters for the first time.
The Treaty: What It Actually Covers
The current US-Belgium treaty is the Convention Between the Government of the United States of America and the Government of the Kingdom of Belgium for the Avoidance of Double Taxation and the Prevention of Fiscal Evasion with Respect to Taxes on Income, signed November 27, 2006, in force from December 28, 2007. It replaced a 1970 treaty and introduced significantly more favorable terms - most notably, 0% withholding on interest and pension fund dividends.
The verified rates from the treaty text:
| Income Type | Without Treaty | Portfolio Rate | Pension Fund | Direct Corporate (80%+) |
|---|---|---|---|---|
| US dividends to Belgian resident | 30% | 15% | 0% | 0% |
| Belgian dividends to US resident | 30% | 15% | 0% | 0% |
| Interest (either direction) | 30% | 0% | 0% | 0% |
| Royalties (either direction) | 30% | 0% | 0% | 0% |
| Capital gains - securities | Varies | Residence country only | Residence country only | Residence country only |
Source: US-Belgium Income Tax Convention (November 27, 2006); US Senate Executive Report 110-2; IRS Publication 515 (2026).
Two features make this treaty unusually favorable compared to most other US treaties:
Interest at 0%. Unlike the US-Australia treaty (10%) or the original US-Belgium treaty (15%), the 2006 treaty eliminates US withholding on interest entirely. Belgian investors holding US Treasuries directly, US-domiciled bond ETFs, or receiving interest from US sources pay no US withholding. This is the same rate as the US-UK and US-Germany treaties.
Pension fund dividends at 0%. Dividends paid to a qualifying Belgian pension fund are exempt from US withholding. This is more favorable than the Australian super fund situation, where the 15% rate applies regardless of whether the fund is in accumulation or pension phase - and also more favorable than the [US-Canada treaty]( /taxes/us-canada-tax-treaty-investors-2026 /)‘s RRSP provisions, which cap the rate rather than eliminating it.
What Counts as a Qualifying Pension Fund
The 0% pension fund rate applies to dividends received by a “pension fund” as defined in Article 3 of the treaty - broadly, entities established in Belgium and regulated under Belgian law whose income is generally exempt from Belgian income tax and whose principal purpose is the administration or provision of pensions or retirement benefits. Belgian OFPs (Organisme de Financement des Pensions), IBPs (Institution de Retraite Professionnelle), and similar regulated pension vehicles qualify. Individual Belgian investors do not receive a 0% rate on their personal holdings - the 15% portfolio rate applies.
How to Claim the 15% Treaty Rate: Form W-8BEN
For Belgian residents holding US stocks or ETFs in a taxable brokerage account, claiming the reduced 15% rate requires Form W-8BEN - filed with the broker or custodian, not with the IRS directly.
Belgian brokers and international platforms used by Belgian investors vary in how they handle this:
- Interactive Brokers: W-8BEN collected at account opening; reliable at applying the correct reduced rate and sends renewal reminders. For smaller portfolios, our IBKR vs IBKR Lite comparison covers which tier fits.
- Bolero (KBC): W-8BEN required for US equity trading; submitted during account registration for international markets.
- Saxo Bank Belgium: W-8BEN completed at onboarding for US market access.
- Keytrade Bank: W-8BEN required for US stocks; submitted at account setup.
- Degiro: W-8BEN process varies; verify directly with the platform that the form is on file and the correct rate is being applied by checking dividend statements.
If you haven’t opened a US-accessible account yet, see our guide to opening a US brokerage account as a non-resident, or compare platforms in our best brokers for international investors roundup.
If you are unsure whether a valid W-8BEN is on file, check your dividend statements. A 30% deduction confirms no treaty rate is being applied. A 15% deduction confirms the treaty rate is in effect. Sophie’s account has shown 15% consistently since she filed at onboarding - confirming the form is active and correctly applied.
W-8BEN expires after three calendar years. A form signed in 2024 expires December 31, 2027. Brokers revert to 30% withholding on expiry. Not all platforms send reminders. Set a calendar alert.
Belgian pension funds and institutional vehicles need to file W-8BEN-E (the entity version) with their US broker or custodian and should document their qualifying pension fund status to access the 0% rate under the treaty.
Belgium’s Double Dividend Tax Problem
Belgian investors holding US stocks face a specific tax structure that differs from most other European countries: US dividends are subject to US withholding at the treaty rate (15%), and then also subject to Belgian withholding tax - the précompte mobilier or roerende voorheffing - at 30%.
The interaction works as follows for a Belgian resident receiving US dividends in a Belgian brokerage account:
Worked example - Sophie’s US dividend income:
- Receives $3,000 gross US dividends
- US withholding at 15% = $450 deducted at source
- Net received in Belgian account: $2,550
- Belgian précompte mobilier at 30% on the gross: $900 deducted by Belgian broker
- Less credit for US withholding already paid: $450
- Net Belgian withholding due: $450
- Total tax: $450 + $450 = $900 (effective 30% on the gross)
- Net received after all withholding: $2,100
The Belgian précompte mobilier is generally a final withholding tax for Belgian individual investors - it does not need to be reported in the personal income tax return, and no further Belgian income tax is owed on dividend income on which the précompte mobilier was correctly levied. The credit for US withholding already paid prevents outright double taxation at the combined rate, but the effective total rate is 30% on the gross.
This is why many Belgian investors prefer accumulating ETFs over distributing ones for their US equity exposure: accumulating funds reinvest dividends internally, bypassing the précompte mobilier entirely. If you’re comparing distributing dividend strategies instead, our JEPI vs SCHD vs QYLD comparison covers the tax tradeoffs. The tax is deferred until sale - and under the pre-2026 rules, that meant indefinite deferral since Belgian CGT on stock gains was generally 0% for private investors. From 2026, deferred gains eventually face the new 10% CGT, but deferral still has value.
Belgium’s New 10% Capital Gains Tax (2026)
This is the most important domestic change for Belgian investors in a generation, and it directly affects anyone holding US stocks from Belgium.
What changed: From January 1, 2026, capital gains realized by Belgian individual residents on financial assets - including shares, ETFs, crypto, and certain insurance contracts - are subject to a 10% tax. Parliament adopted the legislation on April 2, 2026, with retroactive effect from January 1, 2026.
Key features:
- Rate: 10% on net gains above the annual exemption
- Annual exemption: €10,000 per taxpayer (net gains exceeding this are taxed)
- Loss offset: Losses can only be offset against gains in the same year and same category - they cannot be carried forward to future years
- Unused exemption carry-forward: The unused portion of the €10,000 annual exemption can be carried forward up to 5 years, capped at €1,000 per year, bringing the maximum cumulative exemption to €15,000
- Historical gains exempt: Only gains accrued from January 1, 2026 onward are taxable. For assets acquired before that date, the acquisition cost for CGT purposes is the market value on December 31, 2025
- Scope: Applies to Belgian resident individuals. Non-residents are generally outside the scope
What this means for US stocks: A Belgian investor selling US stocks in 2026 or later pays 10% on net gains exceeding €10,000 per year - but only on the portion of the gain that accrued after December 31, 2025. The US treaty’s Article 13 reserves the right to tax such gains exclusively to the country of residence (Belgium), so no US withholding or US tax applies on sale proceeds for Belgian residents.
Worked example - Sophie sells US stocks acquired in 2021:
- Acquired 100 shares at $80 each in March 2021 (total cost: $8,000)
- Market value December 31, 2025: $110 per share ($11,000 total)
- Sold June 2026 at $125 per share ($12,500 total)
- Historical gain (pre-2026, exempt): $11,000 - $8,000 = $3,000 - not taxed
- 2026 gain (taxable): $12,500 - $11,000 = $1,500
- Combined with other 2026 gains, if net gains stay under €10,000 annual exemption: no CGT due
- If total 2026 net gains exceed €10,000: 10% on the excess
The exemption and the step-up in base cost to December 31, 2025 values mean that many Belgian investors with moderate unrealized gains will face limited immediate CGT exposure. The bigger planning question is sequencing gains across years to stay within or near the €10,000 annual threshold.
Sophie’s position illustrates this well. Her total 2026 gains across all US stock sales amount to roughly €8,400 - comfortably under the €10,000 annual exemption. She owes no CGT this year. But she also holds a large accumulating ETF position (IWDA) that has appreciated significantly since 2022. If she sells it in a single year, she would trigger a gain well above €10,000. Her better option is to sell in tranches: realize up to €10,000 in net gains per year, leaving the rest to compound. The pre-2026 step-up means only the gain from January 2026 onward counts - which makes the first two or three years of this regime unusually forgiving for long-term holders. For a real example of how multi-year holding periods and volatility play out, see our TQQQ recovery case study.
The accumulating ETF question: Under the old rules, Belgian investors in accumulating ETFs (like IWDA or CSPX) had indefinite tax deferral on equity gains. Under the new regime, those gains become taxable at 10% when realized. Leveraged funds like TQQQ face a different tax profile for foreign investors and are worth understanding separately. The précompte mobilier on the fixed income component (Reynders Tax) remains separate and is triggered differently - see the Reynders Tax section below. The new 10% CGT applies to the equity gain component only.
Belgian Tax on US Dividends: The Full Picture
For Belgian investors, US dividends are subject to both US withholding and Belgian précompte mobilier. The combined effective rate is 30% on the gross in most cases, as shown in the worked example above. This is the same effective rate as Belgian dividends subject to the précompte mobilier - the treaty rate on the US side simply replaces part of what would otherwise be pure US withholding.
For most Belgian individual investors, dividend income subject to the précompte mobilier is not included in the personal income tax return - the withholding is final. No further Belgian income tax is owed once the précompte mobilier has been correctly deducted.
One exception worth knowing: If your total taxable income is modest enough that your marginal Belgian federal income tax rate falls below 30%, it can be worthwhile to declare dividend income voluntarily in your personal income tax return and claim a credit for the précompte mobilier already withheld. Belgian federal rates start at 25% (on income up to €16,320), so an investor with low total income could reduce the effective rate on dividend income from 30% to 25%. This is an optional election and requires documenting all dividend income and withholding paid during the year.
For investors at higher marginal rates (40% – 50% federal, plus municipal surcharge averaging 7%), the précompte mobilier at 30% is almost always the better outcome - making this purely a consideration for lower-income investors. For Belgian investors weighing income-focused strategies against this backdrop, our REITs vs dividend stocks comparison and best high-yield ETFs guide cover the tradeoffs.
The Reynders Tax: What Accumulating ETF Investors Must Know
Belgian investors in accumulating ETFs face a tax layer that sits between the précompte mobilier and the new 10% CGT: the Reynders Tax (taks op de meerwaarden van fondsen in Dutch, or taxe sur les plus-values des fonds in French).
The Reynders Tax applies to the fixed income (bond) component of gains when selling or redeeming units in certain funds - both accumulating and distributing. The rate is 30%, levied on the portion of the gain attributable to interest and bond income accumulated inside the fund during the holding period.
Who it affects: Investors in mixed funds (equity + bonds) or bond funds domiciled in Belgium or certain other jurisdictions. Pure equity funds (where the fixed income component is below 10% of assets) are generally outside its scope.
The distinction from the new 10% CGT:
- Reynders Tax (30%): Applies to the bond/interest component of fund gains on qualifying mixed or bond funds
- New 10% CGT: Applies to the equity gain component of the same fund, or to gains on pure equity ETFs and individual stocks
For Sophie’s IWDA position (a global equity ETF with negligible fixed income exposure), the Reynders Tax does not apply. The new 10% CGT applies to the full equity gain from January 2026 onward. An investor holding a mixed fund like a global balanced ETF would face both taxes on different portions of the same gain.
Belgian brokers are generally responsible for calculating and deducting both taxes at the point of sale. Check your transaction confirmations to verify which tax has been applied to which component.
Capital Gains on US Stocks: Belgian Tax Only
Under Article 13 of the treaty, gains from selling US securities are taxable exclusively in the country of residence. For Belgian residents, that means:
- No US withholding applies to sale proceeds
- Gains are subject to Belgian CGT rules only (the new 10% regime from 2026)
- The treaty cleanly removes the US from the picture on capital gains
This is the same treatment as under the US-UK, US-Germany, and US-Australia treaties - source-country (US) taxation of portfolio investor capital gains is generally waived in favour of residence-country (Belgium) taxation.
Before 2026: Private Belgian investors in normal wealth management paid 0% CGT on gains from selling shares. Speculative gains (short-term trading, high-frequency) remained subject to 33% + municipal surcharge as miscellaneous income.
From 2026: The 10% CGT applies to gains on financial assets - including US stocks and ETFs - with the €10,000 annual exemption, the historical step-up to December 31, 2025 valuations, and same-year loss offsetting described above.
Intra-year loss offsetting now matters. Under the old 0% CGT regime, there was nothing to offset losses against. From 2026, Belgian investors can use realized losses on losing positions to offset gains on winning ones within the same tax year. Note that losses cannot be carried forward to future years - only same-year, same-category offsetting is permitted.
How the US-Belgium Treaty Compares to Other Major US Treaties
| Country | US Dividends (Portfolio) | Interest | Capital Gains | Pension Exemption |
|---|---|---|---|---|
| Belgium | 15% | 0% | Residence only | 0% |
| United Kingdom | 15% | 0% | Residence only | 0% in qualifying SIPP |
| Germany | 15% | 0% | Residence only | Pension exemption exists |
| Austria | 15% | 0% | Residence only | 0% (Pensionskassen) |
| Japan | 10% | 0% | Residence only | Yes |
| Australia | 15% | 10% | Residence only | 15% (no full exemption) |
The US-Belgium treaty is among the more favorable for institutional investors and pension funds: the 0% interest rate and 0% pension dividend rate match the US-UK and US-Germany treaties. For individual portfolio investors, the 15% US withholding rate is standard - no better or worse than most Western European treaties.
The key distinction from the Belgian investor’s perspective is not the treaty rate but the domestic tax layer on top of it: the 30% précompte mobilier means the effective total rate on US dividends is 30% of the gross, not 15%. This compares unfavorably to a UK investor whose ISA dividends flow free of UK tax, or a German investor whose Abgeltungsteuer (25%) is the final rate with no additional withholding from the US (which is credited).
Common Mistakes That Cost Belgian Investors Money
Not submitting W-8BEN at account opening. If no form is on file, 30% is withheld by the US broker. Check dividend statements for the deduction rate: 15% means the form is working, 30% means it is not.
Letting W-8BEN expire. Valid for three calendar years from signing. Brokers revert to 30% on expiry. Set a calendar reminder.
Expecting the précompte mobilier to disappear on US dividends. Even with the 15% treaty rate from the US side, Belgian withholding tax applies in addition. The US rate is reduced by treaty; the Belgian layer is separate and determined by Belgian domestic law.
Not using the €10,000 annual CGT exemption strategically. From 2026, Belgian investors can realize up to €10,000 in net capital gains per year without paying CGT. Investors with large US stock positions should consider whether to sell in tranches across years to maximize the annual exemption rather than triggering a large gain in a single year.
Ignoring the historical step-up. For US stocks held before January 1, 2026, the taxable gain only includes appreciation from January 1, 2026 onward. The pre-2026 gain is exempt. Many investors do not realize this and either over-estimate their CGT exposure or fail to document December 31, 2025 valuations.
Choosing distributing over accumulating ETFs without considering the tax cost. For US equity exposure, accumulating ETFs defer the précompte mobilier on dividends until sale. From 2026, that deferral eventually meets the 10% CGT - but deferred gains still compound in the meantime. The comparison is not as clear as it was under the old 0% CGT regime, but accumulating structures often remain preferable.
US citizens in Belgium holding Belgian-domiciled funds. Belgian unit trusts, ETFs, and SICAV funds are Passive Foreign Investment Companies (PFICs) under US tax law. The PFIC regime is punitive - gains taxed at the highest ordinary income rate plus an interest charge - and Form 8621 must be filed annually per fund. US citizens in Belgium should generally hold US-domiciled ETFs or direct stocks rather than Belgian-domiciled pooled funds.
Not claiming the US withholding credit against the Belgian précompte mobilier. Belgian brokers are supposed to credit US withholding already deducted against the 30% précompte mobilier due. If your broker is deducting both the full 15% US withholding and the full 30% Belgian withholding without netting, you are overpaying. Check your account statements and raise this with your broker.
Practical Checklist
Belgian resident investing in US stocks (taxable account):
- Confirm W-8BEN is on file - check dividend statements for 15% (not 30%) US deduction
- Renew W-8BEN before expiry (valid three calendar years from signing)
- Verify that your broker is crediting US withholding against the Belgian précompte mobilier (effective total should be 30% on the gross, not 45%)
- Document December 31, 2025 values for all US stock and ETF positions held before that date - this is the base cost for the new CGT
- Plan capital gain realizations across years to use the €10,000 annual CGT exemption
- Offset losses against gains within the same tax year where possible - losses cannot be carried forward
- Capital gains on US stocks: taxable in Belgium only (10% from 2026, above €10,000 exemption); no US withholding on proceeds
Belgian investor preferring accumulating ETFs:
- Confirm accumulating ETF choice avoids précompte mobilier on US dividend income during holding period
- Understand that gains on accumulating equity ETFs now face 10% Belgian CGT on realized gains from January 2026 (the deferral is not eliminated, just eventually taxed)
- Reynders Tax (on bond/fixed income component of gains) remains separate - verify which component of your ETF’s gain is subject to which regime
US citizen living in Belgium:
- File Form 1040 annually including Belgian income, dividends, and capital gains
- Claim Foreign Tax Credit (Form 1116) for Belgian taxes paid - Belgian rates are high enough that the FTC typically eliminates additional US federal tax
- File FBAR (FinCEN 114) if aggregate Belgian account balances exceed $10,000 at any point
- File Form 8938 if total foreign financial assets exceed applicable FATCA thresholds ($200,000/$300,000 single or $400,000/$600,000 joint for residents abroad)
- Avoid holding Belgian-domiciled funds (SICAVs, Belgian ETFs) in accounts where PFIC rules apply; prefer US-domiciled ETFs or direct stocks
- Belgian CGT paid from 2026 may generate foreign tax credits on Form 1116 - track Belgian CGT separately from précompte mobilier
Key Takeaways
Sophie’s situation captures 2026’s specific challenge for Belgian investors: the W-8BEN she filed six years ago has been doing its job quietly, but the domestic tax landscape around it has changed. The 10% CGT she now faces on gains from January 2026 onward is the most significant shift in Belgian investor taxation in decades - and the €10,000 annual exemption combined with the pre-2026 step-up in cost base means the first few years of the new regime are more manageable than they might initially appear.
The US-Belgium treaty is generous by international standards for pension funds (0% on both dividends and interest) and for interest income (0% for all investors). For individual portfolio investors in taxable accounts, the 15% US withholding rate is standard, but the addition of the Belgian précompte mobilier means the effective total rate on US dividends is 30% of the gross - the same as on Belgian dividends. The treaty reduces the US layer; it does not reduce the Belgian one.
The practical priorities for a Belgian investor holding US stocks in 2026 are: confirm W-8BEN is current, document December 31, 2025 valuations for CGT base cost purposes, plan gain realizations across the €10,000 annual exemption, and consider whether accumulating ETF structures still make sense relative to distributing ones under the new CGT regime.
For US citizens in Belgium, the compliance picture is complex but manageable: Belgian income tax rates are generally high enough that the Foreign Tax Credit eliminates most additional US federal tax. The main risk areas are the PFIC classification of Belgian-domiciled funds and the FBAR and FATCA reporting requirements that apply regardless of treaty benefits.
This article is informational only and does not constitute tax or legal advice. Rates are based on the US-Belgium Income Tax Convention (November 27, 2006). Belgian income tax brackets are for assessment year 2026 (income year 2025). The new Belgian CGT was adopted by parliament on April 2, 2026, with retroactive effect from January 1, 2026. Belgian and US tax rules change. Always consult a qualified cross-border tax professional for advice specific to your situation.
Sources: US-Belgium Income Tax Convention (November 27, 2006); US Senate Executive Report 110-2; IRS Publication 515 (2026); FPS Finance Belgium - Tax Rates 2026; Belgian Capital Gains Tax legislation (adopted April 2, 2026, retroactive January 1, 2026) - Loyens & Loeff, Lexgo, EY Belgium; Belgian précompte mobilier rules - FPS Finance; FinCEN FBAR guidance (2025); IRS Form 8938 FATCA thresholds (2025 tax year).
