Who pays corporate income tax
Every company with legal personality established in Belgium is subject to it, whether it is a private limited company, a public limited company or a cooperative. A self-employed person trading as an individual falls under personal income tax instead.
The taxable base is not the accounting profit as it stands. You start from the accounting result, add back disallowed expenses and apply the deductions provided by the Income Tax Code. The gap between the accounting result and the taxable result is often significant.
The reduced rate and its conditions
The reduced rate of 20 % on the first 100 000 € is not automatic. It is reserved for small companies within the meaning of the Code of Companies and Associations, and it requires, among other things, paying a minimum remuneration to at least one company director who is a natural person.
That remuneration threshold rose from 45 000 € to 50 000 € gross per year from assessment year 2026, that is for financial years closed on 31 December 2025 or later (verified on 29 August 2026). A company that paid its director at the old threshold may therefore move to the full rate without having changed anything in how it operates.
A worked example
A company posts 100 000 € of taxable profit and meets the conditions for the reduced rate. It pays 20 000 € of tax. The same company that loses the reduced rate, having failed to reach the director remuneration threshold, pays 25 000 €.
The gap is 5 000 € for a single unmet condition. That is what makes the decision on director remuneration so consequential, and it is a decision taken before the close, not at filing time.
When to file
The corporate income tax return is filed electronically through Biztax. It rests on the approved annual accounts, which is why the two deadlines follow one another closely in a company's calendar.
What people often confuse
Accounting profit and taxable profit are not the same figure. Some expenses booked as costs in the accounts are not deductible for tax purposes and are added back: a company can therefore show a modest accounting result and pay tax that looks out of proportion.
Calculating the reduced rate and steering director remuneration are typically the areas where an accountant adds the most value, because they are decided during the financial year.