10% tax with €10,000 exemption

In 2025, the new Belgian government reached an agreement for the coalition. As part of it, they agreed to introduce a 10% tax on capital gains for financial assets, which became law on 6 April 2026. A capital gain is the profit you make when you sell an investment for more than you paid for it. Up until now, Belgium did not have a capital gains tax on stocks and equity ETFs.

Fortunately, the first €10,000 of capital gains are exempt.

Starting on 1 January 2026

The tax took effect on 1 January 2026. The law itself dates from 6 April 2026 and was published on 21 April 2026. In July 2026, the tax authorities published a long circulaire setting out how they will apply it in practice, which is what this article is based on.

The good news is that it won't apply retroactively. Any capital gains realised up to 31 December 2025 remain tax-free. In other words, you won't pay any capital gains tax for 2025, even though you'll file that tax return in 2026.

All types of financial assets

The tax covers a wide range of financial assets:

• ‍ETFs, as well as index funds, ETNs and ETCs
• Stocks
• Mutual funds
• Bonds
• Foreign currency, with an important exception for ordinary payment accounts that we come back to below
• Investment gold: bars that are at least 99.5% pure, and coins at least 90% pure struck after 1800. Jewellery isn't covered and stays tax-free, as long as you don't trade it for profit.
• Crypto assets, including NFTs
• Financial derivatives like options, futures, and CFDs

Both the assets that you hold within Belgium and outside of Belgium fall under the tax. Anything that isn't on the list is out. The tax authorities name paintings, wine, silverware, sneakers and Pokémon cards as examples of what stays untouched.

€10,000 exemption that grows if you don't use it

The first €10,000 of gains per year per person are tax-free, and that amount is indexed every year so it rises roughly with inflation. If you're married or in a legal cohabitation, your combined exemption becomes €20,000. If the investments are common property, each of you declares half the gain. Children have their own exemption too, which is worth knowing if you invest in your child's name.

If you don't use your exemption in a given year, you build up an extra slice on top of it for later years. It works like this:

• Every year you leave your basic €10,000 untouched, you earn an extra €1,000 for the following year. That amount is indexed too.
• If you do dip into your basic €10,000, next year's extra slice shrinks by the amount you used, and disappears entirely once you've used €1,000 or more of it.
• The extra slices are always used before your basic €10,000. So a small gain that your extra slice covers on its own leaves your basic exemption untouched, and you keep on earning new slices.
• Unused slices stack up indefinitely, but you can only use five years' worth in any single year, so around €5,000.

The extra slice only starts building in 2027, so for 2026 you have the plain €10,000.

Example: a small gain

You sell nothing in 2026, so you earn a €1,000 extra slice for 2027. In 2027 you realise a €900 gain. That comes entirely out of the extra slice, so your basic €10,000 is never touched, and you earn a fresh extra slice for 2028.

Example: a bigger gain

Again you sell nothing in 2026, so in 2027 you have €10,000 plus a €1,000 slice. This time you realise a €2,500 gain. The slice absorbs the first €1,000, and the remaining €1,500 comes out of your basic exemption. Because you used more than €1,000 of the basic exemption, you earn no extra slice at all for 2028.

Costs and taxes are not included in the capital gains calculation

When you sell an investment, it's tempting to subtract all the costs and fees to figure out your "real" profit. But for the capital gains tax, that's not allowed. The law clearly states that no costs or taxes related to buying or selling an asset can be taken into account when calculating your capital gain. This includes broker fees, transaction costs, and the stock exchange tax (TOB). So both your purchase price and selling price are considered gross amounts, before any costs or taxes.

Imagine you buy an investment for €10,000. You also pay €15 in broker fees and €12 in stock exchange tax, so the total amount leaving your account is €10,027.

A while later, you sell the same investment for €13,000. Again, you pay €15 in broker fees and €16 in stock exchange tax, leaving €12,969 on your account.

From your point of view, your profit seems to be €12,969 - €10,027 = €2,942. But for the capital gains tax, those extra costs don't count. The tax authorities calculate your gain as €13,000 - €10,000 = €3,000. Even though you actually earned a bit less, you'll be taxed on the full €3,000 gross gain.

You can offset gains with losses

Realised capital gains can be offset against realised capital losses, as long as they were made in the same tax year. So if you made a €10,000 profit on the sale of a stock, but a €15,000 loss on the sale of another, the result is a net loss of €5,000 so you won't be taxed. You can't carry losses forward to future years.

Losses on any of these investments count against gains on any other, so a loss on crypto can cancel out a gain on shares.

Fund reorganisations are tax-free

When an ETF or investment fund merges with another fund, is split, or is converted into a different compartment, this is not a taxable event. You technically "sell" your shares, but the law doesn't treat it as a realised gain.

This works as long as what you receive back is units in the funds involved in the operation. Both the purchase price and the purchase date of your original units carry over to the new ones, so your position keeps its tax-free past.

Determining the price of purchase

The photo moment: 31 December 2025

According to the government agreement, capital gains earned before the new law takes effect will not be taxed. In other words, profits made before 1 January 2026 will remain tax-free.

To make this possible, the law introduces a special rule for investments that were bought before 2026 but sold after that date. Instead of using the original purchase price to calculate the gain, the law uses the value of the asset on 31 December 2025 as the starting point. This date is called the "photo moment".

From 2026 onwards, your taxable capital gain will therefore be the difference between the selling price and the value of your investment at the photo moment.

Example

You bought an investment in 2022 for €100. On 31 December 2025, it's worth €150. You then sell it in 2027 for €170.

Your total profit is €70 (€170 – €100). But for tax purposes, only the €20 gain that occurred after 2025 is taxable (€170 – €150). The €50 gain made before 2026 remains completely tax-free.

This rule ensures that the new capital gains tax only applies to profits made after the law takes effect, not to gains built up in previous years.

If you invest in foreign currency

Banks don't all use the same exchange rate for 31 December 2025, because they don't look at the same moment of the day. KBC uses the ECB reference rate of around 14:15, BNP and Belfius the London Fix at 17:00, and Saxo often the New York close. The differences show up in the fourth decimal, which on a large portfolio can still mean a few hundred euros.

The tax authorities have settled this: you can simply use the closing rate your own bank or broker publishes, in its app or in the documents it sends you. There's no need to go hunting for an official rate.

When your original purchase price was higher than the 2025 value

In most cases, the value of your investments on 31 December 2025 will be higher than what you originally paid. That means you have an unrealised gain at the photo moment.

But the opposite can also happen. If the original purchase price of your investment was higher than its value on 31 December 2025, you have an unrealised loss at that date.

The law allows an exception in this situation. When you eventually sell the investment, you can use your higher original purchase price instead of the lower 2025 value when calculating your taxable gain. This ensures you're not taxed on earlier losses that happened before the new capital gains tax came into effect.

For example, imagine you bought shares in 2024 for €200. By 31 December 2025, their value has dropped to €150. You then sell them in 2027 for €210. Under this exception, you can use your original purchase price of €200 instead of the lower 2025 value of €150. So your taxable gain is calculated as €210 – €200 = €10. Without this rule, you would have been taxed on €210 – €150 = €60.

There are two conditions to remember. First, the exception only applies to sales made up to 31 December 2030. From 1 January 2031 it expires, and the 31 December 2025 value will always be used as the reference point, even if your original purchase price was higher. Second, claiming your old purchase price can bring your taxable gain down to zero, but never below: it can't create a loss you deduct from other gains.

And if you sell the investment after 1 January 2026 at a loss, you can only deduct the loss that occurred after the photo moment. Losses from before 2026 won't be recognised for tax purposes.

That cuts both ways, and sometimes in your favour. If your investment was worth more at the photo moment than what you end up selling it for, you have a deductible loss for tax purposes, even if you're actually up on what you originally paid.

Selling is in FIFO order

When you invest regularly in the same asset, for example by buying the same ETF every month, you'll likely own multiple batches of that investment bought at different prices.

To calculate your capital gain when you sell, the tax authorities apply the "First-in, First-out" (FIFO) principle. This means that when you sell part of your holdings, the shares you bought first are considered the ones you sell first. So, for each sale, your purchase price is based on the oldest units you still hold in your portfolio. This rule determines which part of your investment is taxed and how much the taxable gain will be.

Example

Let's say you bought the same financial asset three times:

• 10 shares at €100 each in 2026
• 20 shares at €150 each in 2027
• 70 shares at €200 each in 2028

Later in 2028, you sell 25 shares for €200 each. According to the FIFO rule, the first 10 shares sold are from your 2026 purchase, and the next 15 shares are from your 2027 purchase. Your taxable gain is therefore:

• 10 × (€200 – €100) = €1,000
• 15 × (€200 – €150) = €750

Total taxable gain: €1,750

The crucial point is that you have no choice. Even if you would prefer to sell the more recent shares, which would typically yield less profit, the tax authorities strictly apply the FIFO principle.

One useful detail: FIFO runs separately for each securities account. If you hold the same ETF at two brokers, each account keeps its own queue of purchases, so selling at one broker doesn't touch the history at the other.

One average price when you claim your old purchase price

The exception above lets you claim your real purchase price for anything you bought before 2026, until the end of 2030. If you bought the same asset several times back then, you don't go looking for individual purchases. Instead, all your pre-2026 purchases of that asset are pooled into a single average price per unit.

Example

Suppose you bought shares of ETF ABC before 2026:

• 2022: 100 shares at €50 → €5,000
• 2023: 200 shares at €60 → €12,000
• 2024: 150 shares at €70 → €10,500

That's 450 shares for €27,500, so €27,500 ÷ 450 = €61.11 per share. If you claim your old purchase price, all 450 shares count as bought at €61.11.

In this particular case, that wouldn't help you. If the price at the photo moment was €80, the photo moment already gives you a higher starting point than €61.11, so you're better off leaving it alone. The average price is only worth claiming when it comes out above the photo moment value, which means when you were sitting on a loss at the end of 2025.

Outside of this exception you don't need the average at all. By default, every unit you held on 31 December 2025 simply starts from its photo moment value, and FIFO decides which units you're selling.

What if you can't prove what you paid?

If you can't show what you paid for something, the tax authorities treat your purchase price as zero, which means the entire sale counts as a gain. This sounds alarming, but they've made clear it's a last resort, and in practice it mostly affects things you bought after 2025.

For anything you already held before 2026, you don't have to prove what you paid at all. You only have to show that you held it on 31 December 2025, and then the photo moment value becomes your starting point. Any kind of evidence works: statements, invoices, emails, dated screenshots, insurance documents. For crypto, a screenshot of your trading app showing the price on 31 December 2025 is explicitly enough.

That's a relief for crypto investors in particular, where exchanges have gone bankrupt or disappeared and wallet-to-wallet transfers rarely leave a paper trail.

Inherited or gifted investments keep their old purchase price

If you inherit investments or are given them, you don't get a fresh start. Your purchase price is whatever the person who gave them to you originally paid.

Say your parent bought a portfolio for €20,000 and it's worth €30,000 when they die. You inherit it and sell it years later for €35,000. Your taxable gain is €15,000, measured from your parent's original €20,000, not from the €30,000 it was worth when you inherited it.

Inheriting the portfolio, or receiving it as a gift, isn't itself taxed. It's the eventual sale that is, and the taxable gain then reaches all the way back to what your parent paid.

Converting foreign currencies

When you buy or sell investments in a currency other than euro, Belgian tax law requires you to convert both the purchase price and sale price into euro. You must use the exchange rate that applies at the exact moment of the transaction, meaning the rate on the day you buy or sell.

From our own experience, this can feel confusing when exchange rates move a lot. But it matters, because the tax authorities always look at your gain in euro, not in the original currency.

Example

Imagine that in 2026 you buy American shares for $1,000, at a time when the exchange rate is 1 euro = 1.11 dollars. Your purchase value in euro is:

$1,000 dollars / 1.11 = €901

In 2028, you sell the same shares for $1,200. The exchange rate at that moment is 1 euro = 1.20 dollars, so the sale value in euro is:

$1,200 / 1.20 = €1,000

Your capital gain is €99, which is the difference between:

• Sale price: €1,000
• Purchase price: €901

Even though the shares went up in value in dollars, only the gain in euro matters for Belgian capital gains tax.

Exchange rate gains on cash accounts

Many investors who buy individual shares in dollars have a USD cash account linked to their securities account. It makes it easy to carry out multiple transactions in dollars without paying a conversion fee each time.

The catch is that the dollars themselves are taxable. When you buy an American share, you're "selling" dollars from your cash account. If the exchange rate has moved in your favour since you got them, you're realising a gain on the currency. The same applies when you convert dollars back to euros.

There is one important carve-out. Money sitting on an ordinary payment account, the kind of foreign currency account your bank gives you to make payments with, falls outside the tax altogether. The tax authorities excluded it precisely to avoid taxing exchange rate gains on everyday accounts.

Whether a broker's cash account benefits from that carve-out isn't clear, because it isn't a payment account in the usual sense. Until that's confirmed, the safe assumption is that gains on a broker's foreign currency cash balance are taxable and that you have to track them yourself, because your broker won't. FIFO applies here too: the first dollars in are the first dollars out.

One more warning. Even on a genuine payment account, the tax authorities have said that large balances clearly being used to invest can be taken out of this regime and taxed at 33% instead of 10%. A currency account is not a way around the tax.

How the tax is collected by brokers and platforms

The way the tax is collected depends on where your broker or investment platform is based. The rules differ between Belgian and foreign platforms. And even among Belgian ones you'll have the option to "opt out" of automatic tax withholding.

There are essentially three systems:

1. Belgian brokers with automatic tax withholding (opt-in)
2. Belgian brokers with "opt-out": no tax withheld
3. Foreign brokers: no withholding at all

1. Belgian brokers with automatic tax withholding (opt-in)

If you invest through a Belgian broker, bank, or investment platform, by default they will withhold the capital gains tax for you. This is the opt-in system. Your broker deducts 10% of the capital gain at the moment of sale and transfers it directly to the Belgian tax authorities. At the end of the year, you receive a tax statement that lists your sales and the tax already withheld.

This system has what's called a liberating effect. Because the tax is already paid, you don't need to declare these capital gains again in your tax return.

Why automatic withholding isn't perfect

The opt-in system is the most convenient. But it has some drawbacks that can be a dealbreaker to some:

• Losses aren't taken into account. Your broker won't offset capital gains with losses, even though the tax rules allow this.
• The €10,000 yearly exemption is ignored. Even if your total gains for the year are below €10,000, the broker will still withhold 10% on each profitable sale.
• The photo moment applies by default. Brokers will calculate gains using the 31 December 2025 value, even if you bought the investment earlier at a higher price.
• If your broker doesn't know what you paid, it withholds 10% on the entire sale price. You then correct it through your tax return, with your own proof.

This isn't because brokers are being difficult. They simply don't have a full view of your situation. They can't see what you're doing with other brokers or platforms. So by law, they must assume the worst case and withhold the full tax on every sale.

Claim the exemption through your tax return

Because your broker ignores the €10,000 exemption, you need to declare your capital gains on your annual tax return to claim it back. Without filing, you won't get the excess withheld tax refunded.

An interest-free loan to the government

That refund detour comes with two further downsides.

1. It can mean complex calculations on your end
2. It can take a long time before you see the money

Imagine that in January 2026 you sell an ETF with a €7,000 capital gain. It's your only sale that year. Because the first €10,000 of gains per year are tax-free, your final tax bill should be zero. But at the moment you sell, your broker doesn't know whether you'll make more sales later in the year. So they must assume the gain is taxable and withhold 10%. That's €700 deducted immediately. You can reclaim that €700 through your 2026 tax return. But you'll only file that return around June 2027. And the refund may not arrive until mid-2028.

So while automatic withholding makes things simpler upfront, it can also mean giving the government an interest-free loan for up to two and a half years.

Transition period in early 2026

Brokers only became legally obliged to withhold the tax on 1 June 2026, not on 1 January. For sales between 1 January and 31 May 2026, you could ask your broker to pay over an amount equivalent to the withholding tax. That counts as if it had been withheld normally, so you don't have to declare those sales yourself. All the holders of the account have to agree to it.

In practice, most Belgian brokers handled this automatically, covering sales from early 2026 retroactively. The tax authorities have said they will publish separate guidance on this arrangement and on the opt-out, so some of the practical detail is still to come.

2. Belgian brokers with "opt-out" (no tax withheld at source)

To avoid this prepayment problem and the other limitations of tax withholding, the law gives you the option to "opt out" of automatic withholding. If you choose this option, your Belgian broker will not withhold the 10% tax at the moment of sale. Instead, you'll have to report and pay the capital gains tax yourself through your annual personal income tax return.

Why you may prefer to opt out

Opting out makes sense if:

1. You want to offset losses. For example, when you made gains on some investments but losses on others. You can only do this through your tax return.
2. You bought assets before 2026 at a higher price. You might be allowed to use your original purchase price instead of the lower photo moment value, which reduces your taxable gain.
3. You don't want to wait up to two and a half years to reclaim a refund, like in the example above.

The price of opt-out: you do the calculations yourself

The price for this flexibility is that you're responsible for declaring the right amount in your tax declaration. You'll need to calculate your taxable gains yourself, or ask an accountant to help.

Less anonymity, more scrutiny

There's one important downside to opting out. When you declare your capital gains yourself, you lose the discretion that comes with automatic withholding. With opt-in, brokers withhold the tax and pay it to the tax authorities in blocks. But when you opt out, you must declare every taxable transaction directly to the tax authorities.

This gives the tax authorities detailed insight into your investments. For instance, based on this information, they can decide that you're no longer simply managing your own wealth but speculating. If that happens, your gains can be taxed at a much higher 33% rate instead of 10%.

That said, they have to prove it. Your declaration is assumed to be correct, and the burden of showing that you crossed the line into speculation sits with them, not with you.

Several brokers have sent emails to their customers asking if they wanted to opt out.

3. Foreign brokers: no withholding at all

If you use a foreign broker, such as DEGIRO, Trade Republic, or another platform without a Belgian branch, the situation changes completely.

Foreign brokers are not required to withhold the Belgian capital gains tax. They'll simply ignore it. There's also no guarantee that a foreign broker will provide a tax statement compatible with the Belgian system.

This means you'll likely have to:

• Calculate your gains and losses yourself, for every transaction.
• Keep records of all your purchases and sales.
• Declare everything correctly in your annual tax return.

This can be time-consuming and complex, especially if you invest regularly or use multiple platforms.

Comparison: how brokers handle the capital gains tax

The key takeaways are:

• Belgian broker with withholding: easiest option, but you might temporarily overpay and wait for a refund.
• Belgian broker with opt-out: more control and faster access to your money, but you'll need to file the tax yourself.
• Foreign broker: full DIY without withholding and most likely no help (except for Curvo!).

The exit tax when you move out of Belgium

If you live in Belgium and decide to move to another country, you may be affected by what's called the exit tax.

When you move your tax residence out of Belgium, the law assumes that you've "sold" all your investments at that moment, even if you haven't actually sold anything. This means that any unrealised gains (profits that only exist on paper) built up since 1 January 2026 are taxed as if they were realised.

In short: when you leave Belgium, you may owe tax on profits you haven't actually cashed in.

One exception: if you left Belgium in 2026 before 1 May, the day the law came into force, the exit tax doesn't apply to you at all.

You don't have to pay immediately if you move within the EU or EEA

The good news is that Belgium recognises how unfair this would be for people who move frequently for work, especially EU citizens and foreign professionals.

If you move to a country that is part of the:

• European Union (EU),
• European Economic Area (EEA), including Norway, Iceland, and Liechtenstein, or
• any other country with a tax treaty that includes information exchange and cooperation with Belgium,

then you'll automatically get a deferral. This means you don't have to pay the exit tax immediately when you leave Belgium.

Example: an EU employee moving abroad

Let's say you work for a European institution in Brussels and plan to move to Luxembourg in 2026 for a new role. You own a portfolio of ETFs that has increased in value since 2026.

Normally, leaving Belgium would trigger the exit tax, because you're moving your tax residence abroad. But since Luxembourg is an EU country, your tax payment is automatically deferred. You won't have to sell your investments or pay tax on them when you move.

As long as you don't sell those investments within two years, and you continue to live in the EU, the tax obligation will expire after 24 months. You never actually pay the exit tax.

The 24-month "monitoring period"

When you move, the tax deferral lasts for 24 months. During that time:

1. You can't sell the investments covered by the deferral. If you sell part of them, the tax becomes due on that part only, and the deferral continues for the rest. Using the investments as collateral for a loan counts as selling them.
2. You can move again within that period (for example, from Belgium to France, then to Germany), as long as you stay within the EU, EEA, or a treaty country.

Each year, you'll need to send a short confirmation to the Belgian tax authorities showing that you still meet these conditions. If you forget, the deferral ends and the tax becomes payable. The exact form and deadline for that confirmation still have to be set by royal decree.

If you move to a country outside the EU or EEA, or one without a qualifying tax treaty, the deferral isn't automatic. You can still request a delay in payment, but you'll need to provide a financial guarantee, such as a bank deposit or bond, to cover the potential tax amount.

When does the exit tax expire?

After 24 months:

• If you've returned to Belgium, and you didn't sell the investments, the exit tax is cancelled.
• If you've remained abroad, and still hold the investments, the tax obligation expires. You won't owe anything.

Key takeaway

For most foreigners living and working in Belgium, especially those who may move elsewhere in Europe, the exit tax won't create an immediate cost. If you move to another EU or EEA country, your payment is deferred automatically, and the tax liability disappears after two years if you don't sell your investments. But if you plan to move outside Europe, or forget to meet the reporting conditions, you could face a real tax bill on paper gains. So it's smart to prepare before you leave Belgium.

Strategy for Belgian investors

The capital gains tax may change a few practical details for investors in Belgium, but it doesn't change the core principles of good investing.

Harvesting gains and losses

Two moves are worth understanding, and the tax authorities have confirmed that deliberately timing your sales to make the most of your exemptions is not abuse.

The first is selling at a loss to offset gains elsewhere in the same year. That works, but only if you have gains to offset in the first place, and it costs you transaction fees and stock exchange tax, none of which reduce your taxable gain.

The second is selling at a profit inside your €10,000 exemption and buying straight back. There's no waiting period, so you can do it the same day. You pay no tax, and your new higher purchase price becomes the starting point from then on, which shrinks the gain you'll eventually be taxed on.

Three things to weigh before you try it:

• It costs you your extra slice. Dipping into your basic €10,000 is exactly what stops you building the extra €1,000 for next year.
• The round trip isn't free. Stock exchange tax, broker fees and the spread all come out of your pocket, and none of them are deductible. On €10,000 of gain you're saving €1,000 of future tax, so the costs need to stay well below that.
• Don't overdo it. If your trading starts to look like speculation rather than managing your own wealth, your gains can be taxed at 33% instead of 10%. Doing this once a year on a buy-and-hold portfolio is nowhere near that line.

There's also a catch for anything you held before 2026. Selling it replaces your photo moment starting point with a real one, which gives up your right to claim a higher pre-2026 purchase price before 2031. That only matters if you actually paid more than it was worth on 31 December 2025.

And the honest caveat: this is fiddling. It goes against the mindset of a diligent buy-and-hold investor, where you invest calmly, avoid tinkering, and let time do the work.

Stick to the fundamentals

Even with the new tax, the key principles of long-term investing don't change:

• Invest regularly in globally diversified ETFs.
• Stay invested regardless of what the market is doing.
• Follow a disciplined strategy of investing part of your income every month.

The new tax might affect how your broker handles transactions, but it doesn't change why ETF investing works. The most successful investors are still those who buy, hold, and let compound growth do its job, all while relaxing.

Avoid the complexity of foreign currency cash accounts

If you buy individual shares in dollars through a USD cash account, you need to check for exchange rate gains on every movement on that account. This quickly leads to a mountain of calculations.

A simple way to avoid this: invest in ETFs that are denominated in euros. Your broker handles the exchange rate automatically on purchase and sale, and you don't need a separate cash account in a foreign currency. No extra calculations, no extra declarations.

Conclusion

The capital gains tax adds a new layer to investing in Belgium, but it's not the end of the world. With a €10,000 exemption that you can even build up over time, and the ability to offset losses against gains, many of you will barely be affected in practice.

What does change is the admin. You'll need to keep better records of your purchases and sales. You may have to reclaim overpaid tax through your annual return. And if you invest through a foreign broker, you'll be doing all the calculations yourself. These aren't dealbreakers, but they are real hassles.

The good news is that platforms are adapting. Some will withhold the tax automatically. Others, like Curvo, will provide clear guidance and help you report correctly. Either way, the goal stays the same: build wealth steadily by investing in diversified index funds and staying invested for the long term. That's what creates real returns, not clever tax tricks.