Every Belgian company must file an annual corporate tax return with the SPF Finances. We handle the full process — tax calculation, incentive claims, Biztax filing, and advance payment planning.
The corporate tax return (aangifte vennootschapsbelasting/déclaration à l'impôt des sociétés) is a mandatory annual filing for every Belgian company. As part of our accounting services in Belgium, LawSupport prepares and files your corporate tax return via the Biztax platform — ensuring all deductions, incentives, and tax rate benefits are properly claimed.
Advance payments offset — quarterly prepayments (voorafbetalingen) credited against final tax
Advance Tax Payments (Voorafbetalingen)
Belgian companies are expected to make quarterly advance tax payments during the financial year. Companies that do not make sufficient prepayments face a tax surcharge (vermeerdering/majoration) on the unpaid portion.
Quarter
Payment Deadline
Benefit Rate (approx. 2026)
VA1
April 10
Highest benefit (~9%)
VA2
July 10
High benefit (~7.5%)
VA3
October 10
Medium benefit (~6%)
VA4
December 20
Lowest benefit (~4.5%)
Earlier payments receive higher benefit rates, making Q1 payments most advantageous. Our tax advisory team calculates optimal prepayment amounts based on projected taxable income.
Filing Process
Year-end preparation — bookkeeping closing, adjustments, and trial balance
Tax calculation — determine taxable income, apply deductions and incentives
Tax return preparation — complete all sections of the official return form
Quality review — cross-check with annual accounts and prior year return
Biztax filing — electronic submission via Biztax platform
Assessment notice — SPF Finances issues assessment (aanslagbiljet), typically within 6–18 months
Payment / refund — balance due within 2 months of assessment, or refund of overpayment
Common Tax Adjustments
Disallowed Expenses (Added Back to Taxable Income)
The exact deadline varies annually and is set by Royal Decree. For companies with a December 31 financial year-end, the deadline is typically late September or early October of the following year. The SPF Finances publishes the specific deadline each year. Extensions may be granted through an accountant mandate via Biztax.
Corporate tax returns are filed electronically through Biztax, the Belgian government's online tax filing platform managed by the SPF Finances. Paper filing is no longer accepted. Access requires a Belgian eID, Isabel certificate, or mandate from a registered accountant/tax advisor.
Belgian companies must make quarterly advance tax payments (voorafbetalingen/versements anticipés) during the financial year. Payments are due April 10, July 10, October 10, and December 20. Companies that do not make sufficient prepayments face a tax surcharge of approximately 4.5–9% (rate varies annually) on the unpaid portion.
Late filing triggers administrative fines ranging from €50 to €1,250 per infringement. The SPF Finances may also issue an estimated (ex officio) tax assessment, which shifts the burden of proof to the company. Repeated late filing can result in increased penalties and additional scrutiny from the tax administration.
Key documents include: approved annual accounts, general assembly minutes, detailed profit and loss breakdown, tax calculation worksheets, overview of disallowed expenses, advance tax payment statements, dividend distribution records, intercompany transactions (transfer pricing), and any tax incentive claims (IID, investment deduction, NID).
Yes. ITAA-registered accountants and tax advisors can file on your behalf through Biztax using a mandate. This is the standard practice for most Belgian companies. The accountant receives an extended filing deadline (typically 1–2 months extra) when filing through a professional mandate.
After processing your return, the SPF Finances issues an assessment notice (aanslagbiljet/avertissement-extrait de rôle) showing the final tax due or refund. Payment is due within 2 months. If you disagree with the assessment, you can file an objection (bezwaarschrift/réclamation) within 6 months.
Professional fees for corporate tax return preparation typically range from €500–€2,000 for a small BV/SRL with straightforward operations. More complex returns (international operations, transfer pricing, tax incentive claims) can cost €2,000–€5,000+. This is usually included in annual accounting service packages.
File Your Corporate Tax Return With Confidence
We handle tax calculation, incentive claims, and Biztax filing — maximising your deductions.
