Investments, (pension) savings and mortgages – What do you have to declare?

If you're submitting your tax return soon, this overview shows you what you need to declare and which tax breaks you shouldn't miss out on, from interest and dividends to pension savings and mortgages.

1. Savings: When do you have to declare interest?

You do not pay any tax on the first €1,020 of interest per person on a regulated savings account. If you are married or legally cohabiting and the account is held in both names, the amount doubles to €2,040. As long as your income from interest remained below the threshold in 2025, you do not need to take any action. The bank does not deduct any withholding tax and you do not need to include this in your return. If the amount exceeded €1,020 or €2,040, the bank will deduct 15% withholding tax on the amount above the tax-exempt amount. The bank will then pay that amount to the tax authorities.

If you hold several savings accounts with one or more banks, the sum of the total interest accrued may exceed the exempt threshold. Each bank only shows accounts they hold. If the amount of interest accrued across several banks is higher than the threshold amount, you must indicate the excess amount accrued using codes 1151 (for the sole taxpayer, or the oldest in the case of a couple) or 2151 (for the youngest of two taxpayers). Note that interest received by your minor children should also be included. The savings accounts marketed by Keytrade Bank are regulated. You always pay 30% withholding tax on a non-regulated savings account. This will be deducted automatically by the bank and does not need to be declared. The same applies to term deposit accounts.

If you have savings accounts abroad, too, you must indicate this in section XIII of your return and report it to the National Bank of Belgium's Central Point of Contact (CAP).

2. Investments: What does the bank deduct and what action do you need to take?

When you buy or sell investment products on the stock market, you generally pay a tax on stock exchange transactions (TOB). The rates range from 0.12% to 1.32%, depending on the type of product, with a ceiling of up to €4,000. In Belgium, your bank automatically deducts this tax, and you do not need to include this information in your tax return.

If you receive dividends from shares, your bank will usually withhold 30% withholding tax. The same applies to coupons on bonds and to certain payouts from investment funds. In most cases, the withholding tax is a final tax, meaning you do not have to declare the income again.

> Dividend tax exemption: reclaim up to €249.90

This is one area where many investors miss a trick, as you are entitled to an exemption for the first tranche of €833 in dividends per person. This exemption applies to both Belgian and foreign shares, but excludes dividends from investment funds. It is also important to remember that the tax authorities never apply the exemption automatically. You must request it each year in your tax return.

Specifically, this means that if, in 2025, you received €833 or more in dividends on which 30% withholding tax was deducted, you can recover up to €249.90. Even though the withholding tax has already been deducted, you are entitled to a refund through your tax return. To exercise this right, enter the amount of the withholding tax deducted under codes 1437 or 2437. You do not need to state the amount of the dividends.

If you are married or legally cohabiting, each partner is entitled to the exemption individually. Likewise, if you and your partner jointly received more than €833 in dividends, you can split the exemption depending on your matrimonial property regime and ownership relationships. If you hold an investment account together with your children, where you hold the usufruct and the children hold the bare ownership, the usufructuary is legally entitled to the income from the securities account and only the usufructuary can request a rebate of the withholding tax.

> Capital gains on investments are currently not taxed

As a private individual, you do not pay any tax on capital gains. If you sell a series of shares with a profit of €600, you will not be taxed on it in principle. That also means you cannot deduct any losses. This is the case for at least this year's declaration, which relates to your income for 2025. The new capital gains tax will only come into force from the 2026 income year, and will therefore apply to next year's tax return for the first time.

You should note that a capital gains tax already applies to sales in certain investment funds holding a bond component of at least 10%. The bank will deduct the relevant amount automatically, with no action required from you.

> What happens if you speculate on the stock market

Speculation occurs when you take a lot of risk to earn large amounts in the short term, buy and sell often, take out a loan to invest and more. The tax authorities may assess what is classed as speculation on a case-by-case basis. If you speculate on the stock market, any capital gains achieved must be declared and will be taxed at a rate of 33%. You must enter the gains in section XV, under code 1440 or 2440, while any costs may be deducted under code 1441 or 2441. You may also deduct any capital losses from your capital gains.

> Tax on securities accounts

If you hold a securities account with more than €1 million, an annual securities tax of 0.15% may apply. This will usually be handled by your financial institution, too. Find out more about this tax here.

3. Pension savings: A tax break of up to €315 or €337.50

Pension savings remain one of the most accessible tax benefits. The basic ceiling allows you to set aside up to €1,050 in 2025 and receive a tax break of 30% on this amount in 2026 (a maximum of €315). If you opted for the higher ceiling, you were allowed to deposit up to €1,350 in 2025, although the percentage fell to 25% to provide a tax break of up to €337.50.

The amount deposited can be found on the 281.60 certificate you receive from your bank or insurer. The amount is usually already entered under codes 1361 or 2361 in Tax-on-web or in the simplified declaration.

4. Long-term savings: Tax break up to €735

Long-term savings work in a similar way, albeit with higher ceilings. The maximum amount depends on your taxable net professional income and stood at a maximum of €2,450 in 2025. The tax break here is 30%, which corresponds to a maximum of €735. Long-term savings should be entered in section 1353 or 2353. Long-term savings also share the same tax basket as repayments on a mortgage loan, however. Anyone who is still paying off a mortgage that entitles them to a tax break may have little or no room for long-term savings.

5. Rules for mortgages vary depending on your region

The federal interest deduction has now been abolished. This deduction represented a tax break for those who borrowed money for property other than the main family home, such as a second home or an investment property. The benefit has since lapsed for old and new loans. The tax break relating to interest on green loans (taken out between 2009 and 2011) and the federal housing bonus have also been scrapped.

When it comes to your own home, the tax situation depends on the region you live in and when you took out your loan. In Flanders and Brussels, the housing bonus has not existed for new loans for several years, while in Wallonia, the chèque habitat tax relief was abolished for new loans in 2025. If you took out a loan prior to these dates, you can still make use of a transitional arrangement.

6. A few changes

This year's declaration (2025 income year, 2026 tax year) has seen tax breaks abolished for domestic staff, installing a home charging station, premiums for legal assistance insurance, losses on alternative investment funds known as a privateprivak or pricaf privée, energy-efficient homes, adoption fees and electric three- or four-wheeled vehicles. The tax break on gifts worth at least €40 remains in place, but has fallen from 45% to 30%. You should also remember that paper declarations must be submitted by 30 June 2026 at the latest. There are also two deadlines for submitting your declaration online, with 15 July being the deadline for simplified declarations and 16 October the deadline for complex declarations. Around four million Belgians have already received a simplified tax return proposal. While the proposal may be useful, you should always check it is correct. After all, the tax authorities do not have all your income and expenses at their disposal, can make mistakes and do not enter certain benefits as a matter of course.