What is Biztax?
Biztax is the electronic service of FPS Finance, reached through the MyMinfin portal, where Belgian companies file their corporate income tax return. Returns are due by the last day of the 7th month after the financial year-end.
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Example
A company with a 31 December 2025 year-end files its return on Biztax by 30 September 2026. Filing by 28 August 2026 speeds up any refund.
How Biztax works in Belgium
All Belgian corporate tax filings are electronic. The return is prepared and submitted on Biztax. The deadline is the last day of the 7th month following the financial year-end. For financial years ending between 31 December and 28 February, the deadline is fixed at 30 September. If the date falls on a weekend or public holiday, it moves to the next working day.
Companies that file by 28 August for a December year-end get priority refund processing, typically paid by the end of December.
AccountsOS does not connect to Biztax. Finn prepares the figures and tracks the deadline, and you or your accountant submits the return on Biztax.
Related terms
Corporate Income Tax (impôt des sociétés / vennootschapsbelasting) is the tax Belgian companies pay on their taxable profit. The standard rate is 25%, in force since 2020. Qualifying small companies pay a reduced 20% rate on the first €100,000 of profit.
Belgian companies must file their annual accounts with the National Bank of Belgium within 30 days of the General Assembly approving them. The accounts then become public through the Central Balance Sheet Office.
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