What are the audit requirements in Belgium?

Audit requirements in Belgium are governed primarily by the Belgian Code of Companies and Associations (Wetboek van vennootschappen en verenigingen, or WVV) and the legislation implementing EU audit directives. Most small companies are exempt from a statutory audit, but once a company crosses defined size thresholds - or belongs to a regulated sector - it must appoint a certified statutory auditor (réviseur d';entreprises / bedrijfsrevisor). This guide explains who must comply, how the thresholds work, what the auditor does, and what happens when obligations are ignored.

The WVV divides companies into micro, small, medium and large categories. The audit obligation is triggered when a company qualifies as medium or large, or when it is a public-interest entity (PIE).

A company is classified as large if it exceeds at least two of the following three criteria on a consolidated basis: a balance sheet total above a certain threshold, net turnover above a certain threshold, and an average headcount above 250 full-time equivalents. Medium companies exceed two of the lower thresholds set for small companies. The precise monetary figures are set by royal decree and are periodically adjusted; the current thresholds should be verified against the most recent published version.

Public-interest entities are automatically subject to statutory audit regardless of size. PIEs include listed companies, credit institutions, insurance undertakings, and certain other entities designated by law. For these entities, additional rules under the EU Audit Regulation apply, including mandatory auditor rotation and restrictions on non-audit services.

Associations and foundations with significant economic activity also fall within the audit framework once they meet comparable size criteria under the WVV. Foreign companies operating through a Belgian branch must comply with Belgian audit rules to the extent that Belgian law applies to the branch';s accounts.

The threshold test is applied at the end of each financial year. A company that exceeds two of the three criteria for two consecutive financial years becomes subject to the audit obligation from the following year. Conversely, a company that falls below the thresholds for two consecutive years may lose the obligation.

In practice, founders and finance directors sometimes misread the test. A common mistake is applying the thresholds only to the standalone entity while ignoring consolidation rules. Belgian law requires that companies forming part of a group assess whether the group as a whole exceeds the thresholds, even if the individual subsidiary appears small. This catches many foreign-owned Belgian subsidiaries that would otherwise assume they are exempt.

A non-obvious requirement is that the headcount criterion counts full-time equivalents, not legal employees. Part-time workers, temporary staff and certain contractors may need to be included in the calculation. Many underestimate the headcount figure and incorrectly conclude they remain below the threshold.

Consider two practical scenarios. First, a Belgian technology startup with three shareholders, a balance sheet of modest size and 12 employees will almost certainly qualify as micro or small and will be exempt from statutory audit. Second, a Belgian subsidiary of a multinational group with 60 local employees but consolidated group revenues well above the turnover threshold will be caught by the group consolidation rule and must appoint a statutory auditor even if the subsidiary';s own figures appear modest.

Once the audit obligation applies, the company';s general meeting must appoint a réviseur d';entreprises who is a member of the Institut des Réviseurs d';Entreprises / Instituut van de Bedrijfsrevisoren (IRE/IBR). Only registered members of the IRE/IBR may sign statutory audit reports in Belgium. Appointment of an unregistered accountant does not satisfy the legal requirement.

The auditor is appointed for a renewable mandate of three years. For PIEs, the maximum duration of an engagement is ten years, after which a cooling-off period applies before reappointment is possible. The audit committee - mandatory for PIEs - plays a central role in the selection and oversight of the auditor.

The general meeting approves the appointment and sets the remuneration. Belgian law requires that the auditor';s fee be sufficient to allow a proper audit; artificially low fees that compromise audit quality are a ground for regulatory challenge. The auditor';s mandate, remuneration and any early termination must be disclosed in the company';s annual accounts filing.

A common mistake made by foreign founders is delaying the appointment until after the accounts are already prepared. Belgian law requires the auditor to be in place before the financial year to be audited begins, or at the latest at the start of that year. Retroactive appointments are not valid, and the absence of a duly appointed auditor when one is required exposes directors to personal liability.

If your company is approaching the threshold or you are uncertain whether an appointment is required, contact info@vlolawfirm.com. We can help structure the setup correctly the first time.

The statutory auditor';s primary task is to issue an opinion on whether the annual accounts give a true and fair view in accordance with Belgian Generally Accepted Accounting Principles (Belgian GAAP) as set out in the Royal Decree on annual accounts. For consolidated accounts, IFRS as adopted by the EU may apply to certain entities.

The audit opinion is included in the auditor';s report, which is filed together with the annual accounts at the Banque-Carrefour des Entreprises (BCE) / Kruispuntbank van Ondernemingen (KBO) and with the National Bank of Belgium (NBB), which maintains the Central Balance Sheet Office. The report must state whether the accounts comply with the WVV and the applicable accounting framework, and must flag any material misstatements or going-concern issues.

Beyond the financial statements, the auditor reviews the directors'; report (jaarverslag / rapport de gestion) to check consistency with the accounts. The auditor also reports to the general meeting on any irregularities, violations of the WVV or the articles of association, and any facts that may jeopardise the continuity of the company.

For PIEs, the auditor must also produce an additional report to the audit committee, covering the audit methodology, key audit matters and independence confirmations. This additional report is not public but must be available to regulators on request.

Belgian companies must file their annual accounts with the NBB within seven months of the end of the financial year. For companies with a calendar year-end, this means filing by 31 July of the following year. The auditor';s report must accompany the accounts at filing. Late filing attracts administrative fines and, in serious cases, can trigger judicial dissolution proceedings.

The auditor must complete the audit and sign the report before the accounts are approved by the general meeting. The general meeting must be held within six months of the financial year-end. This creates a practical sequencing requirement: the audit must be substantially complete before the general meeting date, which in turn must precede the filing deadline.

Belgian law also imposes interim reporting obligations in certain circumstances. If the auditor identifies a serious and imminent threat to the company';s continuity, the auditor must notify the board in writing. If the board does not take adequate remedial action, the auditor must notify the president of the competent commercial court under the procedure known as the alarm bell procedure (sonnette d';alarme / alarmbelprocedure). This is a legally mandated step, not a discretionary one.

Companies subject to group consolidation must also file consolidated accounts. The consolidating parent must appoint an auditor to audit the consolidated accounts separately from the standalone accounts. The deadlines and filing obligations for consolidated accounts follow the same general framework but with some additional requirements under the WVV.

Failure to appoint a statutory auditor when required is a criminal offence under the WVV. Directors and managers who knowingly omit to appoint an auditor, or who obstruct the auditor';s work, face personal criminal liability including fines. In practice, prosecutions are relatively rare, but regulatory scrutiny has increased following recent EU-level reforms.

Civil liability is the more common risk. If a company suffers loss because accounts were not properly audited - for example, because a fraud went undetected that a statutory audit would have identified - directors may face claims from shareholders or creditors. The absence of a required audit is strong evidence of negligence in such proceedings.

The IRE/IBR also has disciplinary powers over auditors. If an auditor fails to report irregularities or issues an unqualified opinion on materially misstated accounts, the auditor faces disciplinary sanctions including suspension or removal from the register. This creates a strong incentive for auditors to qualify their reports when necessary, which in turn creates reputational and financing consequences for the audited company.

Administrative sanctions include fines imposed by the Financial Services and Markets Authority (FSMA) for PIEs that fail to comply with the EU Audit Regulation. The FSMA has the power to require restatement of accounts, impose public censure and refer matters to the public prosecutor.

What is the difference between a statutory audit and an agreed-upon procedures engagement in Belgium?

A statutory audit is a legally mandated engagement resulting in a public audit opinion filed with the NBB. An agreed-upon procedures engagement is a contractual arrangement where an auditor performs specific procedures agreed with the client and reports factual findings without expressing an opinion. Only a statutory audit satisfies the legal obligation under the WVV. Companies sometimes commission agreed-upon procedures for internal purposes - for example, to satisfy a lender';s requirement - but this does not replace the statutory audit where one is required. The two engagements serve different purposes and are governed by different professional standards.

How long does a statutory audit typically take in Belgium, and what does it cost?

The timeline depends on the size and complexity of the company. For a medium-sized company, the audit process typically runs from two to four months, beginning with planning and interim procedures before the year-end and concluding with the final report after year-end. For a large or listed company, the process may run continuously throughout the year. Professional fees vary significantly by company size, sector and complexity. For a medium-sized company, fees generally start from the low thousands of EUR and can reach the mid-to-high tens of thousands for larger or more complex entities. PIEs subject to the EU Audit Regulation tend to incur higher fees due to the additional reporting requirements.

Can a Belgian company voluntarily appoint an auditor even if it is below the thresholds?

Yes. Any company may voluntarily appoint a réviseur d';entreprises even if it is not legally required to do so. Voluntary audits are common in several situations: where a shareholder agreement requires it, where a bank or investor demands audited accounts as a condition of financing, or where the company anticipates crossing the threshold in the near future and wishes to establish an audit relationship in advance. A voluntary audit carries the same professional standards as a statutory audit and results in the same form of audit report. The appointment process and the auditor';s obligations are identical; the only difference is that the legal sanction for non-appointment does not apply.

Audit requirements in Belgium follow a structured framework built on size thresholds, sector classification and EU-level rules for public-interest entities. Companies that meet the criteria must appoint a registered réviseur d';entreprises, comply with filing deadlines and maintain ongoing engagement with the auditor throughout the year. Non-compliance carries criminal, civil and administrative consequences that can affect both the company and its directors personally.

VLO Law Firms advises international clients on audit requirements in Belgium. We can assist with threshold analysis, auditor appointment procedures, compliance structuring and coordination with Belgian regulatory authorities. To request a consultation, contact: info@vlolawfirm.com