The new capital gains tax will be set at 10% and will apply from 1 January 2026 to capital gains realised on sales of financial assets (such as shares, bonds, funds, savings and investment-type insurance products, etc.).

The tax will apply to natural persons who are subject to personal income tax in Belgium, as well as to certain legal entities that are subject to the tax on legal entities. The latter are mainly non-profit organisations, foundations and private foundations. However, the Bill provides an exception for non-profit organisations that are eligible to receive tax-deductible donations.
Non-residents are not subject to the new tax.

Example
You reside permanently in France and also file your tax return there. You hold your investments in Belgium and when selling certain shares you realise a capital gain. You won't be liable to pay capital gains tax in Belgium under the new measure.

Capital gains realised by a company are outside the scope of the new regime.

Under the new measure, ‘financial assets’ will include a very wide range of financial products such as shares, bonds, funds, options, trackers, ETFs, warrants, savings and investment-type insurance products, guaranteed-rate life insurance (class 21) products, unit-linked life insurance (class 23) products, etc. It will also include crypto-assets. The measure covers both Belgian and foreign assets. Whether or not the assets are listed on an exchange is irrelevant. Unlisted assets will need to be valued using the legally prescribed methodology.

Group insurance products and other contracts within the second pension pillar (occupational pension), as well as pension savings and long-term savings, all fall outside the scope of the new capital gains tax.

Since some bank investment funds are already subject to a specific type of 'capital gains tax', known as the ‘Reynder tax’ (a 30% levy on realised investment gains), it remains to be seen how the capital gains tax liability will be calculated when selling funds to which the Reynder tax also applies. This is not clear at present. The Reynder tax will remain in full force.

In principle, capital gains are calculated based on the difference between the selling price and the purchase price of the asset. As the new measure only takes effect from 1 January 2026, only capital gains accrued from that date will be affected. Historical capital gains are therefore not subject to the tax. The value of an asset on 31 December 2025 (the 'snapshot value’) will used to determine the capital gain.

Example
You bought a share in 2023 at a price of 100 euros, and sell it on 15 September 2026 for 150 euros. In economic terms, you have therefore realised a gain of 50 euros. However, the price of the share on 31 December 2025 is 120 euros. As a result, you pay only 10% of 30 euros (150 - 120) in tax.

If you bought a share before 31 December 2025 at a higher price than the ‘snapshot value’, you will be allowed to use this higher purchase price instead of the snapshot value. It is not yet clear what supporting documents you will need to provide for this. However, this option only applies until 31 December 2030; for transactions which take place after that date, the snapshot value on 31 December 2025 will have to be used in all cases.

Example
You bought a share in 2023 for a price of 150 euros. The price on 31 December 2025 ('snapshot value') is 120 euros. You sell the share on 15 September 2026 for 125 euros . Since the taxable basis is determined in principle by the difference between the selling price and the ‘snapshot value’ on 31 December 2025, a 10% tax should in principle be levied on 5 euros. In reality, however, you did not realise any capital gain, since you bought the share at a higher price than the price you sold it for. Until 31 December 2030, you can apply the historical purchase price that you actually paid.

The volatility of the stock market means it is perfectly possible for you to realise both capital gains and capital losses within a given year. You can deduct those capital losses from the capital gains you realised in the same year.

Example
In 2027, you realise a total capital gain of 25,000 euros by selling various investments. You also sell some investments in the same year on which you realise a loss of 3,000 euros. The net taxable capital gain is then 25,000 - 3,000 = 22,000 euros (leaving aside the basic exemption).

The law will provide for a basic exemption of 10,000 euros for every taxpayer, which will be indexed annually. This exemption will have to be applied for through the individual taxpayer’s tax return.

The law provides for (limited) transferability of the exemption; for every year that you do not use all or part of the basic exemption, you can carry forward 1,000 euros (or part thereof) to a subsequent year, up to a maximum of five years. This means that each taxpayer could potentially achieve a maximum exemption of 15,000 euros. A married couple could therefore end up with a joint basic exemption of 30,000 if they carry forward the full exemption amount (assuming their investments form part of their joint assets).

Example
You do not sell any investments in 2026. You can utilise a basic exemption of 11,000 euros in 2027. If you sell investments which realise a total capital gain of 10,600 euros in 2027, you will not have to pay any capital gains tax in the year 2027.
 

In principle, financial institutions will be responsible for withholding the 10% capital gains tax, except in the case of capital gains realised on certain assets such as crypto-assets, foreign currency, etc..

For non-profit organisation and foundations, the system of withholding the tax at source does not apply; instead, payment of the capital gains tax is arranged directly through the legal entities tax return.

Example
You sell shares in January 2027 and realise a capital gain of 9,000 euros. Your financial institution will deduct capital gains tax of 900 euros on this transaction and will itself forward the money (anonymously) to the tax authorities. Since you can make use of the basic exemption of 10,000 euros, you can declare this capital gain on your tax return for your income year 2027/assessment year 2028 in order to recover the tax paid of 900 euros. However, repayment of this amount will only take place at the earliest at the end of 2028 or during 2029, so in practice you will have to pre-finance the tax for around two years.

To avoid having to pre-finance the tax in this way, the legislator is expected to provide an 'opt out' option. This means you will be able to advise your financial institution that you do not want the tax to be deducted at source and that you will provide the necessary details yourself on your own tax return. On your tax return, you can also set off the realised capital losses and apply the basic exemption.
Since the tax authorities need to be able to verify your tax return, your financial institution will have to provide them with the necessary data ('fiche obligation'). The precise data that must be provided is not yet clear.

For securities that you hold outside Belgium, you will have to declare the realised capital gains yourself on your personal tax return. The system of deducting the 10% tax at source is not possible in this case.

Where a shareholder has a substantial interest in a company whose shares they sell, the capital gains tax rules will differ from the standard regime. This deviating rule aims to treat 'owners' of (family) businesses (which were often founded by themselves or by relatives from a previous generation) less harshly and is designed not to frustrate the entrepreneurial spirit of these 'shareholder-entrepreneurs'.

For the purpose of this rule, a 'substantial interest' is defined as a participating interest of at least 20%. Only the shareholding held by the shareholder themselves and in their personal name is taken into account. Earlier rumours that shares held by family members or held indirectly (e.g. through a management company) might also be taken into account when determining the 20% minimum threshold are therefore no longer an issue. Moreover, the assessment of the 20% participation condition takes place at the time of the transaction itself. It is therefore not enough that you have held a 20% stake at some point in the (recent) past; only the situation at the time of sale is relevant. There is no ‘transitional regime’ for shareholders who do not reach the minimum threshold of 20%, but only own, say, 19% of a company's shares; they will therefore fall under the 'standard regime' of 10% tax and a 10,000 euro basic exemption.

Shareholders who do meet the condition will benefit from an exemption on a first tranche of 1,000,000 euros when realising a capital gain. Higher capital gains will be taxed at a progressive rate (1.25% up to 2,500,000 euros; 2.5% up to 5,000,000 euros; 5% up to 10,000,000 euros; 10% for 10,000,000 euros and above). The exemption is expected to apply once per five-year period.

The deviating regime applies to capital gains on shares of both listed and unlisted companies. For unlisted companies, the question naturally arises as to the 'initial value' of the shares (the 'snapshot value’ on 31 December 2025). A number of options are given for determining this value. If a transaction took place in 2025 (e.g. a sale of shares), the value used in that transaction can be used as the reference value (‘snapshot value’). In other cases, a standardised valuation method (four times EBITDA plus shareholders' equity) can be used. You may also have a detailed valuation carried out by an auditor or certified accountant. Taxpayers are expected to be able to choose the method that yields the highest valuation. However, the taxman has the option to dispute the value.

For the sake of clarity, the scheme is not limited to shares of operating companies. It therefore also applies in principle to capital gains realised on the sale of shares of, for example, a family holding company, a management company or a holding company.

Ultimately, the introduction of a capital gains tax on financial assets does not change the basic principle that the transactions in question should still fit within the normal management of a private asset. 'Normal management' is traditionally defined as 'acts performed by a prudent and reasonable person for the purpose of day-to-day management, but also with a view to the profitability, monetisation and reinvestment of elements of his assets'.

If transactions do not fall within this framework of ‘normal management’ (and are therefore classed as 'abnormal management'), realised capital gains will be deemed to be ‘miscellaneous income’ and subject to a tax rate of 33% (+ supplementary local tax). The question of whether or not a transaction falls within the definition of ‘normal management’ is obviously a question of fact, on which only a court can provide a definitive ruling.

Case law uses various criteria to judge whether the realisation of a capital gain forms part of the ‘normal management’ of a private asset. One of the transactions considered here involves 'speculation'. Some cryptocurrency holders, for example, who had hoped that the introduction of a 10% ‘solidarity contribution’ (capital gains tax) would exempt them from the potential application of a tax rate of 33% (+ supplementary local tax) on their capital gains, will thus potentially miss out. 
Another familiar example of potentially 'abnormal management' concerns 'internal capital gains'. In such transactions, a shareholder/natural person realises a capital gain on selling their shares to another company (holding company) incorporated or controlled (directly or indirectly) by the seller. The tax authorities (and the finance minister) considered that such a situation did not constitute ‘normal management’. However, given that the judgement regarding ‘normal management’ can only be made by a court with jurisdiction over the substance of the matter, the case law is more ambiguous on this point.

The regime in relation to ‘internal capital gains’ is now being tightened up and embedded in legislation. When a shareholder sells shares to a company in which that shareholder exercises control (alone or in conjunction with family members), a separate levy of 33% will apply to the capital gain.

Capital gains realised when contributing shares to a holding company will however still be tax-exempt. In fact, a specific regime already applies for the contribution of shares, whereby the capital for tax purposes of the company which receives the contribution is limited to the acquisition cost of the contributed shares. From a tax perspective, the net contribution is deemed to be a 'taxed reserve', which is subject to 30% withholding tax upon subsequent distribution.