Capital gains tax

What is capital gains tax?

This is a 10% tax on the capital gain you realise from the ‘transfer for consideration of a financial asset’. This rather legal term means that this capital gains tax applies to the sale of your securities and to certain Corporate Actions.

The financial instruments concerned are essentially:

• shares (listed or unlisted)
• bonds
• investment funds
• trackers (e.g. ETFs) and
• derivatives such as options, futures or swaps

This tax therefore also applies to your Keyplan or Keyprivate, if you have one.

No capital gains tax is applied to pension savings funds.

When will the capital gains tax come into effect?

The capital gains tax was due to come into effect on 1 June 2026. However, it was decided to apply it from 1 January 2026 and to implement it in two phases as outlined in point 'How is the tax withheld?'

Who is subject to the capital gains tax?

This 10% capital gains tax applies to natural persons with a tax residence in Belgium and to certain legal entities (such as non-profit associations and foundations) that are subject to corporate tax in Belgium.

Natural persons with a tax residence outside Belgium and legal entities (such as companies that are subject to corporate income tax) are exempt from capital gains tax.

Is the capital gains tax applied by every financial institution?

The capital gains tax applies wherever your financial instruments are held. Whether it is a Belgian financial intermediary (such as Keytrade Bank) or a foreign bank or financial institution, the capital gains tax remains applicable.

If you hold financial instruments with a foreign institution, as a taxpayer you must, in principle, determine the taxable base yourself, calculate the capital gains tax and declare it in your personal income tax return.

How is the capital gains tax calculated?

For financial instruments acquired on or after 1 January 2026, the taxable capital gain corresponds to the positive difference between the selling price of those financial instruments and their purchase price.

For financial instruments acquired before 1 January 2026, the taxable capital gain is calculated as the positive difference between the selling price of those financial instruments and their value on 31 December 2025. In other words, any capital gain you realised before that date is not subject to capital gains tax.

For example:

• In 2019, you bought 100 ABC shares for EUR 95 per share.
• On 31 December 2025, their value was EUR 180. For the purposes of the capital gains tax, this EUR 180 serves as the reference value.
• If you sell these shares in 2027 at a price of EUR 230, the difference between EUR 230 and EUR 180 will be taxable.

There is then a capital gain of EUR 50 per share, which means that the capital gains tax will be EUR 5 (10% of EUR 50) per share.

In this simple example, no transaction costs or any other taxes associated with the transaction were taken into account.

How do you calculate the capital gains tax if the purchase price was higher than the reference value of the financial instrument on 31 December 2025?

If you purchased a financial asset before 31 December 2025 at a higher price than the final reference value for capital gains tax on 31 December 2025, you can declare this original purchase price yourself in your personal tax return. This allows you to reduce your capital gains tax.

However, Keytrade Bank, like all financial intermediaries, will only take into account the reference value of the asset as at 31 December 2025.

For example:

• You bought an ABC share for 120^EUR in March 2024.
• On 31 December 2025, this share was worth 100^EUR .
• In 2026, you sell it for 130^EUR .

A) Keytrade Bank’s calculation of capital gains tax:

• 130^EUR selling price - 100^EUR reference value = 30^EUR capital gain
• The tax will therefore be 3^EUR here.

B) Calculation by FPS Finance after you have declared the actual purchase price in your personal tax return:

• 130^EUR selling price - 120^EUR actual purchase price = 10^EUR capital gain
• The tax will be 1^EUR here.

How is capital gains tax calculated for a financial instrument that you have purchased several times and at different prices?

For purchases made from 1 January 2026, when you have acquired the same instruments multiple times at different prices, the FIFO method ('First In, First Out') applies. This means that, for the purposes of capital gains tax, the securities you purchased first are treated as having been sold first.

Example 1:

• On 5 February 2026, you buy 80 ABC shares for 30^EUR per share.
• On 15 April 2026, you buy 120 additional ABC shares for 35^EUR per share.
• You therefore have 200 shares in total.

If you sell 80 shares in 2028 at 55^EUR , your profit will be calculated on the basis of the first purchase. So:

• The selling price: 55^EUR
• The purchase price taken into account: 30^EUR
• The capital gain per share amounts to: 55 – 30 = 25^EUR
• The total capital gain on the sale = 80 (shares) x [55 (selling price) - 30 (purchase price)] = 2000^EUR
• The tax therefore amounts to 200^EUR , i.e. 10% of the total capital gain.

Example 2:

• On 30 November 2025, you purchased 100 DEF shares for 25^EUR per share. Subsequently, on 15 December 2025, you will purchase 50 additional shares for 45^EUR per share, i.e. 150 shares in total.
• On 31 December 2025, the DEF share was quoted at 40^EUR per share.

If in 2026 you decide to sell 100 DEF shares at the price of 55^EUR per share, this means:

• The selling price: 55^EUR
• The purchase price: 40^EUR (Keytrade Bank must take into account the price as at 31 December 2025, regardless of your actual purchase price)
• The capital gain per share amounts to: 55 – 40 = 15^EUR
• The total capital gain: 100 x 15 = 1500^EUR

The tax therefore amounts to 150^EUR , i.e. 10% of the total capital gain.

Example 3:

On 16 January 2026, you purchased 50 GHI shares for 40^EUR per share and then 50 additional shares for 60^EUR per share on 20 June 2026, i.e. 100 shares in total.

If you decide to sell 100 GHI shares in 2028 at a price of 50^EUR per share, this means:

For the first 50 shares sold:

• Purchase price: 40^EUR
• Selling price: 50^EUR
• The capital gain per share amounts to: 50 – 40 = 10^EUR
• The total capital gain of the first 50 shares: 50 x 10 = 500^EUR

For the following 50 shares:

• Purchase price: 60^EUR
• Selling price: 50^EUR
• The capital gain per share amounts to: 50 - 60 = - 10^EUR (in this case you will therefore realise a loss)
• The total loss in value of the 50 shares: 50 x (-10) = - 500^EUR

This gives you a total capital gain of 0^EUR on your sale. No tax will then be charged.

How is capital gains tax calculated on profits in foreign currencies?

For securities denominated in foreign currencies, exchange gains and losses are included in full in the taxable basis for capital gains tax. The tax is always determined in euros.

Keytrade Bank converts the amounts of purchases and sales transactions virtually into euros in order to calculate the taxable capital gain.

As a result, an increase in the value of a foreign currency relative to the euro can also generate a taxable capital gain. It does not matter whether the instrument is bought or sold via an account in the relevant currency or via an account in euros: the value of each transaction is always virtually converted into euros, even if there is no actual currency exchange at the time of the transaction.

Example:

You buy a share for 1200^USD . At that time, the EUR/USD exchange rate is 1,20 (1^EUR = 1,20^USD ). The cost price for purchasing the share is therefore 1000^EUR .

You sell this share later at the same price of 1200^USD , without realising any gain in local currency (in this case in USD). In the meantime, however, the dollar has risen and the exchange rate is 1,10 (1^EUR = 1,10^USD ). The equivalent value in euros on sale is then EUR 1.090,91.

In this example, the taxable capital gain amounts to EUR 90,91 (1.090,91 – 1.000), solely due to changes in the exchange rate. The capital gains tax then amounts to EUR 9.09 (10% of the capital gain).

It is therefore important to know that a financial asset can be sold at a lower price than the purchase price in a certain currency and may be subject to capital gains tax if the change in the exchange rate has yielded a profit.

Does Keytrade Bank take into account any realised capital losses in the same year when calculating capital gains tax?

No. Like all financial intermediaries established in Belgium, we withhold capital gains tax from the very first euro of profit on a sale (in the case of an ‘opt-in’). In doing so, we do not take into account any realised losses in that year.

Under certain conditions, the taxpayer may claim these capital losses in their personal tax return. In order to be deductible, these capital losses must have been realised in the same year by the same taxpayer.

Losses before 31 December 2025 are not taken into account. In practice, only losses will count if you sell an instrument at a lower price than its reference value on 31 December 2025.

Is there an exemption when applying the capital gains tax?

Yes, every taxpayer enjoys an annual exemption of EUR 10.000 on capital gains made, and this exemption means that no tax is due on your first 10 000^EUR in capital gains (at least if you apply for your exemption via your tax return).

Keytrade Bank will, when withholding the capital gains tax (like all Belgian financial intermediaries), however not take this exemption into account. In the case of an ‘opt-in’, the tax is withheld by our bank from the very first euro of capital gain.

To actually benefit from the exemption in the case of an ‘opt-in’, you must therefore apply for it yourself as a taxpayer via your annual tax return.

In concrete terms, this means that you must apply for the exemption for the year 2026 via the tax return you submit in 2027 (tax year 2027, income year 2026). You will then, in principle, be reimbursed before the end of 2028.

This amount should be indexed annually and can be carried over to a limited amount in case of partial use: up to 1000^EUR per year, for a maximum duration of five years. This will make it possible to build up a cumulative exemption of up to 15 000^EUR .

For example, if you do not realise any capital gains in 2026 and 2027 (or if you do not claim a refund during that same period), you can therefore transfer 1000^EUR exemption per year, i.e. a total of 2000^EUR . Your available exemption for the year 2028 is therefore 12 000^EUR (10 000^EUR basis + 2000^EUR transferred).

Is there also capital gains tax on a gift or inheritance?

No. There is only capital gains tax on the actual realisation of a capital gain. A gift or transfer by inheritance therefore does not immediately lead to a taxable capital gain, as in this case the beneficiary of the gift or the inheritance takes over the financial asset. There is no sales involved.

If the beneficiary wants to sell that asset afterwards, the original acquisition value of the financial asset will of course apply for the calculation of any taxable capital gain.

How is capital gains tax withheld?

The Law introducing the Capital Gains Tax on Financial Assets provides for an automatic withholding tax at source. This means that Keytrade Bank can withhold the tax directly for you.

However, this law has not yet entered into force. Therefore, no automatic withholding can be carried out at present. A distinction must therefore be made between two periods:

• Period from 1 January 2026 to 31 May 2026
  • During this period Keytrade Bank cannot yet automatically withhold the tax. However, the law does allow you to ask the bank to proceed with the withholding for this period, a so-called 'opt-in'.
  • If you opt for this option, Keytrade Bank will send you a statement of the capital gains you have made during this period after the law comes into force. The tax will then be withheld by us via your trading account… and transferred by us to the Belgian tax administration.
  • Please note that this 'opt-in' option can be exercised until 31 August 2026.
• From 1 June 2026
  • From 1 June 2026, Keytrade Bank will automatically withhold capital gains tax.
  • However, you may ask the bank not to carry out this withholding automatically. In that case, you are opting for a so-called 'opt-out'. In the event of an opt-out, Keytrade Bank will not withhold any tax and will not make any payment to the Belgian tax authorities. You will then have to declare all your capital gains yourself in your personal tax return.
  • Please note: the 'opt-out' option can only be requested until 31 August 2026 (or before the occurrence of a taxable transaction) and will therefore be applied for the two periods described.

If you do not communicate your choice to us, you will automatically be considered as an 'opt-out' for the period from 1 January 2026 to 31 May 2026 and as 'opt-in' from 1 June 2026.

Is the choice for an opt-in/opt-out per account, per account holder or per bank?

A choice for opt-in or opt-out is made at the level of each account individually. You cannot therefore choose a single opt-in or opt-out that applies to all accounts for which you are the holder or co-holderat our bank. For a joint account, the opt-in or opt-out must be approved by each of the co-holders.

If not all co-holders expressly agree, Keytrade Bank must:

• apply an opt-out for the period from 1 January 2026 to 31 May 2026 and therefore not withhold the tax
• apply an opt-in from 1 June 2026 and therefore withhold the tax.

How and when do you choose to opt in or opt out at Keytrade Bank?

We will contact you shortly with more information. However, it is not yet possible to opt-in or opt-out for your accounts with our bank.

How does Keytrade Bank opt-in and opt-out for securities accounts with more than two holders?

If you hold an account with two (or more) other persons, for example if you are a member of an investment club or joint ownership, you will have to communicate the choice of opt-in/opt-out via a manual procedure.

A valid choice requires the unanimous agreement of all holders.

Is it possible to change from opt-in to opt-out and vice versa when applying the capital gains tax?

For the current year, you can still change your choice of opting in or opting out of a securities account until the time of your first taxable event on that account. Our bank will then apply your most recent choice.

Do you still want to change again? If so, this choice will only take effect the following year.

Example 1:

• On 1 January 2027, you opted for the ‘opt-in’.
• On 15 March 2026, you change your choice and switch to ‘opt-out’.
• A taxable event occurs on 10 April 2026 (for example, a sale that generates tax).
• The choice applicable for the whole of 2026 will be the 'opt-out', as it was in force before the first taxable event.

Example 2:

• On 1 January 2027, you opted for the ‘opt-in’.
• 10 February 2027: a taxable event occurs
• 15 March 2027: you request to switch to the 'opt-out'
• In that case, the 'opt-in' will continue to apply for the entire year 2027.
• The opt-out will only take effect from 1 January 2028.

How is the capital gains tax applied to several securities accounts with different banks?

With an opt-in, the capital gains tax is withheld at source from each securities account separately, regardless of where you hold that securities account. Whether you are with one or more banks, the capital gains tax application is per account. No consolidation is possible within one bank or between banks.

Who chooses to opt in or opt out for a minor child’s securities accounts?

The legal representative. If you have opened a securities account or a Keyplan in the name of a child, you, as the legal representative, must decide whether there will be an opt-in or opt-out for this account.

Please note: if there are two legal representatives on behalf of a minor, one of them is sufficient.

Can holders of a securities account with power of attorney choose to opt in or opt out for the account on which they have power of attorney for the purposes of capital gains tax?

No. Only holders of a securities account can opt in or opt out.

Is the capital gains tax applicable when the securities account is held jointly by a Belgian tax resident and a non-resident?

Yes. If you have opted for an opt-in whereby the bank automatically withholds tax at source, the capital gains tax will apply to the entire capital gain realised. In other words, the distribution of ownership of the securities between the Belgian tax resident and the non-resident is not taken into account.

This means that the non-resident will then have to apply for the repayment of their share of the withheld capital gains tax to the Belgian tax authorities.

What are the bank’s reporting obligations with regard to the tax authorities?

Even when customers opt for the 'opt-out' and our bank does not withhold tax on taxable capital gains, an automatic exchange of information takes place between our bank and the tax authorities.

Incidentally, this exchange does not mean that your capital gains will automatically appear in your tax return. You are obliged to declare them yourself in your personal tax return. This information will not be included in a pre-filled tax return.

Thanks to this data exchange, the tax authorities can verify whether the capital gains have been voluntarily declared by the taxpayer.

How does the bank calculate any capital gain on a transfer of securities?

When transferring securities to your Keytrade Bank accounts, you must provide us with proof of the purchase price.

If your purchase price is not confirmed, Keytrade Bank (like any financial intermediary) must assume that the purchase price is equal to 0. This is of course unfavourable when calculating the taxable capital gain.

We therefore recommend that you keep all your purchase receipts from 1 January 2026. Don't have them anymore? Be sure to ask your original financial institution before initiating the transfer.

Example:

On 23 March 2026, you buy 10 ABC shares for a total amount of EUR 1,000 from bank XYZ. On 15 June 2026, you transfer these securities from bank XYZ to Keytrade Bank. On 17 February 2028, you decide to sell the 10 shares for an amount of EUR 1,500.

• If you have provided proof of the purchase price at the time of transfer:
  • The realised capital gain is 1,500 - 1,000 = 500^EUR .
  • The tax due (10%) is therefore 50^EUR .
• However, if you did not provide proof of the purchase price:
  • Keytrade Bank must consider the purchase price as zero.
  • The capital gain then amounts to 1,500 - 0 = 1500^EUR .
  • The tax due (10%) in this case is 150^EUR .

The lack of proof therefore leads to a three times higher tax in this example.

How does the capital gains tax take into account the Reynders tax?

The so-called “Reynders tax”, i.e. a tax of 30% on the realised capital gain on certain bond funds, remains applicable in parallel with the capital gains tax.

However, there is no question of double taxation: the portion of the capital gain that is already subject to the Reynder's tax is excluded from the taxable base of the new capital gains tax.

How is capital gains tax determined on purchased options? (Long options)

• If you buy an option and sell it at a profit, a capital gains tax of 10% applies to the realized gain.
• If you buy an option and exercise your right to buy shares (call option) or sell shares (put option) at the strike price, then that strike price becomes the selling price (for a put option) or the purchase price (for a call option) when calculating the capital gain between purchase and sale.

Example of a CALL:

• You buy an option that gives you the right to purchase 10 shares at a strike price of 50^EUR .
• You exercise your option and buy 10 shares at 50^EUR each (total = 500^EUR ). The strike price of 50^EUR is used by Keytrade Bank as the “starting price” for calculating the capital gain.
• Later, you sell these shares at 70^EUR each (total = 700^EUR ).
• Capital gain: 700 – 500 = 200^EUR Capital gains tax (10%) = 20^EUR

Example of a PUT:

• You buy an option that gives you the right to sell 100 shares of XYZ at a strike price of 50^EUR .
• By exercising the option, you sell 100 shares of XYZ at 50^EUR (total 5000^EUR ). This strike price (50^EUR ) is considered the selling price for calculating the capital gain.
• You had purchased these 100 shares on 05/01/2026 at 40^EUR (total 4000^EUR ).
• Capital gain: 5,000 – 4;000 = 1000^EUR Capital gains tax (10%) = 100^EUR

How is capital gains tax determined on written options? (Short options)

Scenario 1:

You write (sell) an option and receive a premium. If the option expires worthless, you keep the premium and no capital gains tax is due.

Scenario 2:

You write an option and later buy it back at a lower price, for example to reduce your exposure or benefit from favorable market movements. In that case, the realized gain is subject to a 10% tax.

Example:

• You write 1 option contract and receive a premium of 100^EUR
• You later close the position by buying back the option for a premium of 60^EUR .
• Capital gain = 100 – 60 = 40^EUR Capital gains tax (10%) = 4^EUR

Scenario 3

You write an option and are then required to buy shares (put option) or sell shares (call option). The strike price is used as the purchase price (if you must buy) or the selling price (if you must sell) for calculating the capital gain.

Example: written put

• You write a put option with a strike price of 50^EUR , where 1 contract represents 100 units of the underlying asset.
• The option is exercised, and you buy 100 shares at 50^EUR each (total = 5000^EUR ).
• You later sell these 100 shares at 70^EUR each (total 7000^EUR ).
• Capital gain = 7.000 – 5.000 = 2000^EUR Capital gains tax (10%) = 200^EUR

Example: written call

• You write a call option with a strike price of 100^EUR , where 1 contract represents 10 units of the underlying asset.
• The option is exercised, and you sell 10 shares at 100^EUR each (total 1000^EUR ).
• You had previously purchased these 10 shares on 01/02/2026 at EUR 50 each (total 500^EUR ).
• Capital gain = 1.000 – 500 = 500^EUR Capital gains tax (10%) = 50^EUR