Belgian capital gains tax: what it means for your investments

10% tax with €10,000 exemption

In January 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. 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.

Starting on 1 January 2026

The tax will be introduced on 1 January 2026 but won't be applied retroactively. In practice, this means that any capital gains earned before 31 December 2025 will remain tax-free. No capital gains tax needs to be paid for the year 2025, even though you'll fill in that tax declaration 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
• Currencies
• Commodities like gold
• Crypto assets, including NFTs
• Financial derivatives like options, futures, and CFDs

€10,000 exemption that can increase to €15,000

The first €10,000 of gains per year per person are tax-free. This amount will be indexed each year, meaning that it will more or less follow inflation

If you don’t use your entire exemption, part of it can be carried forward to the next year:

• Only 1/10 of the annual exemption (so €1,000 if the exemption is €10,000) can be carried forward each year.
• You can accumulate unused portions up to a maximum of five years, meaning the total carry-forward cannot exceed €5,000.
• When you use your exemption in a given year, you must first use the oldest carried-over amounts. This is called the FIFO principle, “first in, first out”.

So if you don’t use your full exemption, you can carry over €1,000 per year, up to a total of €5,000. This allows your maximum exemption to grow from €10,000 to €15,000 if unused for five years.

Example

Let’s say you don’t sell any of your investments in 2026. This means you don’t use your €10,000 annual exemption. The tax rules allow you to carry forward one tenth of that amount, or €1,000, to the next year.

In 2027, your exemption is now €11,000. If you again don’t use it, you can carry forward another €1,000. Your exemption for 2028 then becomes €12,000.

You can keep doing this for up to five years. Each year that you don’t use your exemption, you carry forward €1,000, up to a maximum of €5,000. After five years, your total exemption can therefore grow to €15,000 (€10,000 annual exemption + €5,000 carried over from previous years).

If you then realise a capital gain, the first €15,000 of profit will be tax-free.

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.

Determining the price of purchase

Snapshot on 31 December 2025 for assets purchased before 2026

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 often referred to as the “snapshot moment” or “photo moment”.

From 2026 onwards, your taxable capital gain will therefore be the difference between the selling price and the value of your investment on 31 December 2025.

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.

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 so-called “snapshot 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 is a key condition to remember: this exception only applies to sales made up to 31 December 2030. From 1 January 2031, the exception expires. After that, the 31 December 2025 value will always be used as the reference point, even if your original purchase price was higher.

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

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.

You must be able to prove the purchase price

If you can’t prove how much you originally paid for an investment, the Belgian tax authorities will assume your purchase price is zero. That means the entire selling price will be considered a taxable capital gain.

This rule is especially relevant for crypto investors. Many early adopters bought their first Bitcoins or Ethereums years ago on exchanges that no longer exist. If you can’t prove those original purchase prices, the tax office may treat the full value of your crypto as taxable profit.

How the tax will be collected by brokers and platforms

When the new capital gains tax comes into effect on 1 January 2026, the way it’s collected will depend 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
2. Belgian brokers with “opt-out” (no tax withheld at source)
3. Foreign brokers: no withholding at all

1. Belgian brokers with automatic tax withholding

If you invest through a Belgian broker, bank, or investment platform, the capital gains tax will usually be withheld automatically every time you sell an investment with a profit. This is called “withholding at source”. Your broker will immediately deduct 10% from your profit and transfer it to the Belgian tax authorities. At the end of the tax year, they’ll also send you a tax statement that lists all your sales and the tax already withheld.

This system has what’s called a “liberating effect”. It means that you won’t need to declare these capital gains again in your tax return. The tax has already been paid.

However, there’s a catch. Belgian brokers can’t take into account any of the following when they calculate the tax:

• Losses you may have made on other investments.
• Your €10,000 annual exemption.
• A higher purchase price if you bought the asset before 2026 (when the “snapshot” rule applies).

Because your broker doesn’t have a full view of your portfolio across all platforms, they must assume the worst case and withhold the full 10% on every sale.

Why this can be inconvenient

Imagine you sell an asset in January 2026 with a €70,000 gain. Your broker will immediately withhold €7,000 (10%). But because the first €10,000 of capital gains are tax-free, you actually don’t owe any tax on this transaction.

The problem is that your broker doesn’t know that. They’re legally required to withhold the tax anyway. You’ll have to wait until your 2026 tax declaration, which you file in June 2027, to claim that €7,000 back. The refund might take a few additional months to arrive.

So while automatic withholding makes things easy, it can also mean you temporarily lend money to the government.

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 before the start of the tax year, 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 some investors may prefer to opt out

Opting out can make 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 snapshot value, which reduces your taxable gain.
3. You don’t want to wait nearly two years to reclaim a refund, like in the example above.

The downside

If you opt out, you’ll need to do the calculations yourself or with the help of an accountant. You’ll also lose the discretion that comes with automatic withholding, since you’ll be declaring all transactions directly to the tax authorities. Still, your Belgian broker will probably continue to send you an annual tax report with all the necessary details to make this easier.

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 new 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.

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 do, the tax becomes due immediately in Belgium.
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.

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 ETF investors

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

Tax-loss harvesting only if it makes sense

Some investors might be tempted to sell ETFs at a loss to offset other gains and lower their tax bill. This can work, but it comes with transaction costs, stock exchange tax, and the risk that you’ll miss out on future gains if the market rebounds soon after you sell.

In practice, it’s hard to get right. And 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 very 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.

Conclusion

The new 10% capital gains tax changes how you'll need to think about selling your investments from 2026 onwards. But it doesn't change the fundamentals of good investing. You still benefit most from buying globally diversified ETFs, holding them for the long term, and letting compound growth do its work.

With a €10,000 exemption and the ability to offset losses, most Belgian investors will face a limited tax bill, especially if they follow a long-term buy-and-hold strategy. And if you use a Belgian broker or a platform like Curvo, much of the admin will be handled, though you may need to claim refunds through your tax return.

The key is to stay calm and stick to your strategy. Don't let tax rules push you into unnecessary selling or complex manoeuvres. Focus on what matters: regular investing, patience, and time in the market.