Each year, more than 40,000 Belgian companies pay an administrative fine for late filing of their annual accounts. The average amount hovers around €400, but can reach €1,200 for large structures. The good news: these fines are 100% avoidable. Here's the calendar.

Annual accounts filing — BNB

For a financial year matching the calendar year (December 31, 2025), the ordinary general assembly must be held within six months after closing — so before June 30, 2026. Accounts must then be filed with the National Bank within 30 days after the AG and at the latest 7 months after closing, i.e. July 31, 2026.

Past this date, the fine starts at €400 and increases in tranches. Past 8.5 months of delay, the company can be considered presumed bankrupt. This is not theoretical: the enterprise court automatically receives the list of late filers.

UBO register update

Any change in the structure of beneficial owners must be notified to the UBO register within one month. And above all — this is the most frequently forgotten point — an annual confirmation is mandatory, even if nothing has changed. This confirmation must occur within the year following the last update.

Penalty for omission: administrative fine of €250 to €50,000. Unlike accounts filing, the UBO fine is not automatic, but the SPF Finances stepped up controls in 2025.

VAT return and client listing

For monthly VAT taxpayers: return and payment by the 20th of the following month. For quarterly: the 20th of the month following the quarter. The annual client listing (operations exceeding €250 excl. VAT per Belgian client) must be filed before March 31, 2026 for 2025 operations.

Mandatory publications in the Belgian Official Gazette

Any statutory modification (change of purpose, registered office, capital, directors, managers) must be published in the annexes of the Belgian Official Gazette within 15 days after the notarial deed or AG decision. Failure to publish makes the modification unenforceable against third parties — which can cost dearly in the event of a dispute.

Other deadlines to watch

Professional withholding: the 15th of the following month. ONSS declaration: the month following the quarter. Corporate tax: within 6 months of closing for companies with a shifted financial year. Forms 281.50 (director remuneration and fees): before June 30, 2026 for 2025 services.

The underlying logic

Belgian tax and corporate law operate on a simple principle: any delay is presumed to be a fault. There's no grace period, no friendly reminder, no additional deadline "just this once". Penalties fall automatically, sometimes several months after the fact, when you've forgotten them.

The countermeasure is mechanical: a consolidated internal calendar, a designated owner per deadline, and a quarterly review. We provide this personalised calendar as part of the Essential package — it's often the first thing our clients set up, and the one they most regret not having had before.