Capital gains tax in 10 questions
A tax on capital gains from financial assets has been introduced in Belgium since 1 January 2026. Below, we summarise the most important points for you.
1. Who does this new tax apply to?
The capital gains tax on financial assets applies to:
- Private individuals subject to personal income tax in Belgium
- Entities subject to Belgian legal entities tax (such as non-profit associations and foundations), with the exception of those that are entitled to receive tax-deductible donations.
Do you have a company? This new tax does not apply to you: any capital gains you realise are already subject to corporate income tax.
2. Which financial assets are subject to taxation?
The capital gains tax applies to:
- Shares, listed or unlisted1
- Bonds
- Investmentsfunds and ETFs (trackers)1
- Derivative products, like options, futures and swaps
- Financial life insurance products (branches 21, 23 and 262)
- Physical gold3
- Foreign currency
- Cryptocurrencies3
The following remain outside the scope of the tax:
- Pension savings
- Long-term savings
- Group insurance schemes
- Physical precious metals other than gold (silver, platinum, palladium, etc.)3
- Dividends and interest on which you already pay 30% withholding tax
1 The Reynders tax on bond funds remains in force next to the new capital gains tax. The 2 taxes are applied separately: 30% withholding tax on income from the bond portion (Reynders tax) and 10% tax on the balance of the gains* on sale (capital gains tax)
2 In practice, the capital gains tax will rarely apply to branch 26, as withholding tax generally already applies.
3 Not offered by BNP Paribas Fortis.
3. How is the capital gains tax calculated?
Taxable capital gains
You only pay tax on the capital gains you ‘realise’. This means: on the profit* you make from, for example, the sale of shares or bonds. So the tax is not levied on your total selling price, but on the positive difference between the purchase price and the selling price (i.e. before costs and taxes).
Example:
- In 2026, you buy 10 shares at €100 each.
- In 2028, you sell these 10 shares at €130 each.
Your total selling price of 10 × €130 = €1,300 is not taxable. It is your gain of 10 × (€130 − €100) = €300 that is taxed.
In the case of staggered purchases - for example, if you bought the same share in company X at different times, the FIFO principle (First In, First Out) applies when selling. The tax authorities consider the shares you purchased first to be the ones you sell first.
Example:
- In 2026, you buy 20 shares at €100 each.
- In 2027, you buy a further 20 shares at €120 each.
- In 2029, you sell 30 of these shares at €150 each.
It is not your total selling price of 30 × €150 = €4,500 is taxable, but your gain of €1,300. The tax is calculated as follows:
- 20 × (€150 − €100) = €1,000
- 10 × (€150 − €120) = €300
Rate and exemption
The basic rate is 10%. The first €10,000 per taxpayer per year is exempt from tax (€20,000 for married couples under the community of property regime). This amount will be indexed each year.
Example:
- In 2026, you buy 10 shares at €100 each.
- In 2028, you sell these 10 shares at €130 each.
The capital gains tax amounts to 10% on your gain of 10 × (€130 − €100) = €300, i.e. €30. You can use your available exemption to recover these €30 via your tax return for that income year.
4. How is the taxable capital gain calculated for investments made before 2026?
Only capital gains realised as from 1 January 2026 are taxable. It was therefore important to determine the value of your investments accurately as at 31 December 2025. In accordance with the regulations, your bank therefore took a ‘snapshot’ of your portfolio on that date. By default, the taxable capital gain is the difference between the value of your investment at the time of this snapshot and the higher price you have received or receive when you sell it as from 1 January 2026.
Example:
- In 2023, you buy 10 shares at €80 each.
- At the time of the snapshot on 31 December 2025, these 10 shares are worth €100 each.
- In 2028, you sell the 10 shares at €130 each.
Not your total gain of 10 × (€130 − €80) = €500 is taxable, only your gain since the time of the snapshot, i.e. 10 × (€130 − €100) = €300
5. What happens if the ‘snapshot value’ is lower than my purchase price?
If, as at 31 December 2025, the value of your investment was lower than its purchase price, the taxable capital gain calculated on the basis of the snapshot will be higher than your actual gain.
Example:
- In 2023, you buy 10 shares at €100 each.
- At the time of the snapshot on 31 December 2025, these 10 shares are worth €80 each.
- In 2028, you sell your 10 shares at €130 each.
Your capital gain calculated on the basis of the snapshot amounts to 10 × (€130 − €80) = €500, while your actual gain is 10 × (€130 − €100) = €300. However, the bank is required to withhold 10% capital gains tax (in case of opt-in) on €500 instead of €300. The difference of €50 – €30 = €20 may be reclaimable under certain conditions via your tax return.
For staggered purchases, the weighted average purchase price of the investments you held on 31 December 2025 is used.
Example:
- In 2024, you buy 20 shares at €90 each.
- In 2025, you buy a further 20 shares at €100 each.
- At the time of the snapshot on 31 December 2025, these 40 shares are worth €80 each.
- In 2027, you sell 30 of these shares at €110 each.
Your weighted average purchase price for the 40 shares is ((20 × €90) + (20 × €100)) / 40 = €95. Based on the snapshot value, your capital gain amounts to 30 × (€110 − €80) = €900, but based on your weighted average purchase price, it amounts to 30 × (€110 − €95) = €450. You can therefore reclaim €45 in capital gains tax via your tax return.
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6. How is the capital gains tax collected?
Entities must always report their realised capital gains themselves in accordance with the rules of corporate income tax.
For private investors, automatic withholding by the bank (withholding tax) is the standard collection method. However, while realised capital gains will be taxable from 1 January 2026, automatic withholding will only apply from 1 June. Capital gains realised during the transitional period from 1 January to 31 May must therefore, in principle, be reported by you in your 2026 income tax return. Avoid this dual situation by confirming your choice of either ‘opt-in’ (withholding at source) or ‘opt-out’ (self-declaration) for the entire year 2026 by 31 May at the latest.
Compare both options:
| OPT-IN (withholding at source) |
OPT-OUT (self-declaration) |
| The bank automatically deducts 10% from any capital gains you realise and anonymously pays this tax to the tax authorities. | The bank does not deduct 10% of any capital gains you realise and therefore does not pay any capital gains tax to the tax authorities. |
| The bank is not obliged to report your 2026 capital gains to the tax authorities in 2027. | The bank is obliged to report your capital gains to the tax authorities. |
| At the beginning of 2027, the bank will provide you with an overview of all capital gains and losses realised in 2026. | At the beginning of 2027, the bank will provide you with an overview of all capital gains and losses realised in 2026. |
| In principle, you are not obliged to include all 2026 capital gains in your tax return for the tax year 2026, unless you wish to utilise the annual exemption of up to €10,000 and/or offset realised capital losses. | You are obliged to declare all 2026 capital gains realised in your tax return for the 2026 income year. |
| To claim an exemption and/or offset losses, you must report realised capital gains up to the amount of the exemption and/or deduction. This must be done via your 2026 income tax return. As a result, it may take up to 2 years before you receive (partial) reimbursement of the withheld capital gains tax from the tax authorities. |
You can immediately apply the annual exemption of up to €10,000 in your declaration and/or offset any losses. So you never pay more tax than actually owed. |
Capital gains from foreign securities, cryptocurrencies, foreign currency or physical gold must always be declared, regardless of whether you opt-in or opt-out.
7. What if I haven’t made an opt-in or opt-out choice by 31 May 2026?
We are legally required to apply the standard collection method:
- Opt-out (self-declaration) from 1 January to 31 May 2026
- Opt-in (automatic withholding tax) from 1 June 2026 until any revocation in subsequent years
8. Is the €10,000 capital gains exemption automatically applied under opt-in?
No. You must always claim the exemption yourself via your tax return, even if you opt for opt-in (withholding at source). In this case, you must still declare (in part) your realised capital gains, up to the amount of the exemption you wish to claim.
If you do not use the first €1,000 of your annual exemption until €10,000, or do not use it in full, you may transfer the unused part to subsequent years. You can do this for up to 5 consecutive years. In this way, you can build up an exemption of up to €15,000 (€30,000 for married couples under the community of property regime) if you have not claimed it during the previous 5 years.
When claiming an exemption, any transferred exemption is used first, before your basic exemption of €10,000.
Example 1:
| Year | Available exemption | Capital gain realised | Transferred exemption | Basic exemption | Transferrable exemption |
| 2026 | €10.000 | €0 | N/A | -€0 | €1.000 |
| 2027 | €11.000 | €1.000 | -€1.000 | -€0 | €1.000 |
| 2028 | €11.000 | €0 | -€0 | -€0 | €1.000 |
Example 2:
| Year | Available exemption | Capital gain realised | Transferred exemption | Basic exemption | Transferrable exemption |
| 2026 | €10.000 | €0 | N/A | -€0 | €1.000 |
| 2027 | €11.000 | €1.500 | -€1.000 | -€500 | €500 |
| 2028 | €10.500 | €0 | -€0 | -€0 | €1.000 |
Example 3:
9. Are capital losses tax-deductible?
That depends on the situation:
- Capital losses realised on a sale before 1 January 2026 are not deductible (likewise, gains realised on a sale before 2026 are not taxable). You therefore cannot offset them via your tax return.
- If you sell an investment at a loss as from 1 January 2026, you may deduct that capital loss, but only from capital gains you realised in the same year. You cannot carry these capital losses forward to subsequent years.
- You may also temporarily offset the negative difference between your higher purchase price and the lower snapshot value of your investment. This is only possible if the sale takes place within 5 years following the snapshot, i.e. up to and including 31 December 2030.
10. What do I always have to declare myself?
Whether you choose to opt in or opt out, you must always make a personal declaration yourself in the following cases:
- If you have realised capital gains on foreign securities accounts or on the sale of foreign currency, cryptocurrencies or physical gold
- If you wish to claim an exemption from the tax
- If you wish to offset realised capital losses
- If you wish to claim the difference between the capital gains tax based on the ‘snapshot value’ and the higher purchase price you paid for your investment before 1 January 2026