If you are a natural person, you can choose:
1) Automatic withholding at source (default option).
2) Personal tax return (opt-out)
Non-profit organisations subject to the tax must declare their realised capital gains to the tax authorities via form 273.
"}},{"accordionList":[{"richBody":{"value":"In practice
ING automatically withholds the tax at source and pays it to the tax authorities.
You are not obliged to declare the realized capital gains in your tax return.
Do you want to take advantage of the exemption of 10,000 euros and/or deduct any capital losses? You can do this through your tax return. You can rely on the annual overview that we will send you or on the account statements of the executed transactions.
What does the ‘automatic withholding at source’ involve?
The system combines simplicity with fiscal anonymity, since the capital gains for which the tax has been withheld do not need to be declared again.
Good to know
If you want to deduct capital losses or benefit from the exemption, you must include the capital losses and capital gains in your tax return.
Capital gains realized through foreign institutions are never automatically taxed. In this case too, you must declare them correctly in your tax return.
In practice
You can activate the opt-out via Home'Bank or the ING Banking app. Make sure you are using the latest version of the app, available on the App Store (iOS) or Google Play (Android).
You are obliged to declare the realized capital gains in your tax return.
ING must inform the tax authorities about the transactions for which the tax has not been withheld (= reporting obligation).
At the beginning of the next fiscal year, ING will provide you with an overview of the capital gains and the capital losses.
This annual overview will help you to fill in your tax return correctly.
If there are multiple account holders, all account holders need to activate the opt-out so that the tax is not deducted from the capital gains realized on the account.
What does the opt-out mean?
With the opt-out, you avoid paying a tax in advance that you might not owe. For example, if the taxpayer can benefit from the tax exemption of 10,000 euros in his tax return or deduct realized losses.
Points of attention
However, this choice requires strict monitoring: all transactions must be recorded, supporting documents must be kept, and the tax rules must be well understood, because any error or omission in the declaration can have tax consequences.
If this choice involves multiple investment accounts with different financial institutions, the follow-up becomes particularly complex without the help of a financial advisor.
ING is required by law to provide the Belgian tax authorities with information on sales transactions of financial instruments held in an investment account for which the opt-out has been activated (= reporting obligation).
This requirement for detailed reporting results in a loss of anonymity, because the tax authorities will have a full view of the capital gains realized.
ING reports to the tax authorities the total amount of capital gains realised on the account over the entire year, for all persons who are or have been account holders during that year. This also applies if they were no longer account holders at the time of certain transactions. Each client remains individually responsible for correctly reporting, in their tax return, the share of the capital gain that relates to them.
If there are multiple account holders, the detailed declaration will cover all account holders.
The tax applies to capital gains realised from 1 January 2026. Due to the delayed adoption of the law, a transitional period was in place from 1 January to 31 May 2026, before the final regime came into effect. During this period, capital gains were already taxable, but banks were not yet able to withhold the tax at source or report it to the Belgian tax authorities.
What does this mean for you?
1. You chose automatic withholding at source (default option)
2. You chose opt-out
You must declare all capital gains for 2026 yourself, including those realised during the transitional period.
You can activate the opt-out via Home'Bank or the ING Banking app. Make sure you are using the latest version of the app, available on the App Store (iOS) or Google Play (Android).
A straightforward flow is available from your investment account.
Important: If you have multiple investment accounts, you must indicate your choice separately for each investment account for which you want to activate the opt-out.
For example, it is perfectly possible to activate the opt-out for your ING Self Invest account and to opt for withholding at source for your ING Invest Advice account.
Don't have the ING Banking app or Home'Bank yet? Follow these steps to install it.
Need help accessing the digital flow?
Our colleagues in the branch will be happy to help you at the digital devices in the customer area.
You can activate the opt-out via Home'Bank or the ING Banking app. Make sure you are using the latest version of the app, available on the App Store (iOS) or Google Play (Android).
A straightforward flow is available from your investment account
You can activate the opt-out via Home'Bank or the ING Banking app. Make sure you are using the latest version of the app, available on the App Store (iOS) or Google Play (Android).
A straightforward flow is available from your investment account
Step 1: one of the account holders follows the standard procedure.
Step 2: The other holders will receive a notification ‘Document to sign’ in the ING Banking app or in Home'Bank. All account holders must consent (= sign) within 30 days so that the opt-out is activated.
Why?
The agreement of all account holders ensures that everyone is aware of the fiscal and administrative consequences of the opt-out.
ING then provides the legally required information about each co-holder of an investment account with an opt-out to the tax authorities.
Your choice has different tax implications depending on when you activate the opt-out and whether any taxable transactions have already taken place (such as a sale with a capital gain or a corporate action).
SITUATION 1
You activate the opt-out on 20 July 2026, before a sale with a capital gain or before a corporate action.
When does the opt-out apply?
------------
SITUATION 2
You activate the opt-out on 20 July 2026 and you carried out transactions with capital gains between 1 January 2026 and 31 May 2026.
When does the opt-out apply?
------------
SITUATION 3
You activate the opt-out on 20 July 2026 and you carried out transactions with capital gains between 1 June 2026 and 19 July 2026.
When does the opt-out apply?
------------
SITUATION 4
You activate the opt-out on 17 February 2027, before a sale with a capital gain or before a corporate action.
When does the opt-out apply?
Quite simply, by following the same steps as when activating the opt-out (see the section ‘How do you activate the opt-out if you are the sole holder of the investment account?’ above).
On the second screen, answer “no” to the question: ‘Do you wish to deactivate the withholding at source of the capital gains tax?’. Then confirm your choice (electronic signature).
Unlike the opt-out, the return to withholding at source does not need to be validated by all account holders. In other words, it is sufficient for one of the account holders to revoke the opt-out for withholding at source to apply to the account again from the following year.
"},"title":"Activating the opt-out"},{"richBody":{"value":"Once activated, the opt-out remains valid until it is revoked. Revocation can only take place once per tax year and will only take effect from the following year.
How can you revoke the opt-out?
Quite simply, by following the same steps as when activating the opt-out (see the section ‘How do you activate the opt-out if you are the sole holder of the investment account?’ above).
On the second screen, answer “no” to the question: ‘Do you wish to deactivate the withholding at source of the capital gains tax?’. Then confirm your choice (electronic signature).
Unlike the opt-out, the return to withholding at source does not need to be validated by all account holders. In other words, it is sufficient for one of the account holders to revoke the opt-out for withholding at source to apply to the account again from the following year.
"},"title":"You have opted out and changed your mind. How should you proceed?"},{"richBody":{"value":"For all the details about the tax (persons and financial assets involved, calculation method, etc.), we invite you to consult our dedicated page.
"},"title":"More info on the capital gain tax"},{"richBody":{"value":"