Every year, filing a tax return remains a delicate exercise for many taxpayers. With new legislation, technical sections, and pre-filled information, mistakes are common and can prove costly through additional taxes, interest, or penalties.
This article highlights eight recurring pitfalls observed among employees, self-employed individuals, and pensioners, and suggests several useful reflexes to avoid them.
Blindly relying on pre-filled data
Electronic tax returns contain more and more pre-filled information: salaries, pensions, mortgage loans, pension savings, etc.
However, this information remains entirely the responsibility of the taxpayer: incorrect or incomplete data may lead to a tax adjustment, even if the information originally comes from a third party (employer, bank, insurer).
Before signing the return, it is therefore essential to systematically compare each amount with the documents received (forms 281.10, 281.11, 281.20, bank statements, tax certificates).
In case of discrepancies, the relevant field should be manually corrected and, if necessary, a corrected form should be requested from the institution responsible for the error.
Not making use of opportunities for favourably taxed income
Not all income is taxed in the same way, and some benefit from a more favourable tax regime (investment income within certain limits, miscellaneous income at a reduced rate, the copyright regime, etc.).
Many taxpayers limit themselves to the traditional salary-income structure and overlook the possibility—when legally justified—of structuring part of their income in categories that are more tax-efficient.
In compliance with anti-abuse rules, it may be useful to consult a professional to determine whether certain services (creative or intellectual work, or the transfer of rights) could be classified differently and thus benefit from a more favourable tax rate.
Incorrectly declaring professional expenses (flat-rate vs. actual expenses)
Many individuals automatically benefit from a flat-rate deduction for professional expenses, calculated according to legal percentages.
Opting for actual expenses can sometimes be advantageous (long commuting distances, training, equipment), but it requires that each expense can be supported by documentary evidence in case of a tax audit.
A common mistake is deducting actual expenses without properly assessing the impact: some taxpayers give up the flat-rate deduction for a minimal—or even non-existent—tax benefit while exposing themselves to a more thorough review. Conversely, some taxpayers (particularly the self-employed) opt for the legal flat-rate deduction even though their tax benefit would be significantly higher if they declared their actual expenses.
Overlooking tax benefits related to family circumstances
Family circumstances directly influence taxation: the tax-free allowance, dependent children, shared custody, alimony payments, and the status of legal cohabitation or otherwise.
Errors often occur after recent changes (separation, blended families, birth of a child, or an adult child continuing studies).
Forgetting to declare a dependent child or incorrectly allocating children between parents may result in an unnecessarily heavy tax burden for one of them. Particular attention must also be paid to the child’s own income (student job, scholarship, alimony) in order to avoid losing the status of dependent.
Poor management of tax deductions for mortgage loans
The tax regimes applicable to the main residence have changed significantly in recent years and now vary depending on the region of residence (Wallonia, Flanders, Brussels) and the date the loan was concluded.
Many taxpayers continue to apply the old rules automatically without verifying whether their situation still falls within a transitional regime.
It is essential to correctly identify the type of tax benefit that applies (deduction, regional tax reduction, transitional system) and the allocation key when there are multiple borrowers.
Underestimating the tax implications of investment income and foreign accounts
Belgian interest and dividends are often subject to a final withholding tax, which generally means they do not need to be included in the tax return, except in certain cases (reduced rate, exemption threshold exceeded, etc.).
For foreign investment income or bank accounts held outside Belgium, however, vigilance is essential: they must in principle be declared, even if they have already been taxed abroad.
Moreover, holding a foreign account (or an investment insurance contract) must be reported both in the tax return and to the National Bank, failing which sanctions may apply.
The argument of the “forgotten account” is becoming increasingly unacceptable in the era of automatic exchange of information between states.
Not adapting your wealth structure to your family situation
Marriage, legal cohabitation, de facto cohabitation, the presence of children, joint ownership or otherwise: family and wealth structures directly influence the tax burden.
Yet many couples maintain an organization of their assets and income that is no longer optimal in light of their evolving circumstances (purchase of property, blended families, approaching retirement).
From a tax perspective, it may be relevant to review the distribution of assets (full ownership, usufruct/bare ownership), the choice of matrimonial property regime, or the ownership of certain income streams (rental income, investment income) between partners.
Wealth planning that is coordinated with succession planning can often significantly reduce tax burdens in the long term, while strengthening legal security within the couple and for their children.
Forgetting to correct or challenge in time
Even after the tax return has been submitted, corrections may still be possible within certain deadlines through an amended return or a reasoned objection.
Many taxpayers let time pass, pay an additional tax that could be contested, or react too late to a tax assessment notice they nevertheless consider unjustified.
The deadlines for filing an objection are strict and generally begin to run from the date the tax assessment notice is sent.
Failing to act in time often means definitively waiving any right of appeal, even if the administration’s decision is based on a clear error.
In a tax environment that is becoming increasingly technical—whether it concerns the annual tax return, the structuring of your income, or the preparation of your estate—it is essential to anticipate and make coherent choices rather than simply bearing the tax burden.
Vanbelle Law Boutique assists individuals, self-employed professionals, and companies in implementing tailored solutions: optimization of the tax burden, wealth structuring, succession planning and, where necessary, assistance in any exchanges or disputes with the tax authorities. Together with our partners at VB Tax & Accountancy (www.vb-alliance.com), we can also take care of your tax return and its follow-up.
.png)
