The capital gains tax is one of the most notable tax changes for 2026. Over the past few weeks and months, a lot has been said, written and, above all, speculated about. Now that there is quietly more clarity, we answer the most frequently asked questions.
Please note that the bill has not yet received a final vote, so details may change. We are following developments closely and will keep you informed.
Last updated: December 12, 2025
What is capital gains tax, how is it calculated and what are the exemptions?
Everything we already know about the capital gains tax today can be found in this item. Please note: Keep in mind that as of today, this bill has not received a final vote.
Is the capital gains tax final yet?
After months of negotiations, on the fringes of the budget agreement also gave a ruling on the capital gains tax. Under the Summer Agreement, the tax would be due on capital gains that will be realized as of January 1, 2026, but with the postponement of the budget talks, that law becomes no longer approved this year.
The De Wever government has now decided to make the tax next year retroactive enter, so she does start running from New Year's.
Please note: the current legal text is a design, and has yet to be voted on.
When does the capital gains tax go into effect?
If all goes as planned, the tax Effective retroactively as of Jan. 1, 2026, even if the law is not voted on until later.
There would be a transition period be provided (from Jan. 1 until the law effectively takes effect), in which banks will pay the capital gains tax not yet automatically withhold on a sale. Only if explicitly requested by the customer would the bank do so. Those who do not request the deduction would have to declare the fee later in the tax return.
Important: banks do not take into account the exemption or offsetting of capital gains. So anyone who wants to take advantage of it must declare the capital gain themselves anyway.
What are the concerns and pitfalls?
- Technical preparation banks: Banks can theoretically refuse to withhold tax if they are not technically ready. In that case, you are required to file your own tax return.
- Equality principle: If some customers can have deductions made through the bank and others cannot, the principle of equality may be compromised.
- Administrative burden: You must be able to prove purchase and sales prices, as well as the value on 31/12/2025. Without this information, a correct declaration is impossible.
Do you need to take action right now?
Our general advice for now is to not to take irreversible steps as long as the legislative framework is not final. However, it is prudent at this time to make all documentation collect that can support the value of your portfolio on 31/12/2025 (think estimation reports, valuations, and so on).
In files with small stakes in natural persons (1 share, 1% of shares etc.) it may be useful to have these shares still to be transferred this year (2025) to a corporation, to avoid discussions and valuation problems.
Do you have questions about this? Then be sure to contact your customer manager.
Still have questions about capital gains tax?
The bill around the capital gains tax has still not gone through the full parliamentary process and is thus not yet voted. This process takes time, and until an official publication in the Official Gazette occurs, nothing has been definitively decided.
We are monitoring this closely and will communicate appropriately as soon as there is more clarity. Do you have any pressing questions in the meantime? Then of course you can contact your customer manager.