The audit in companies, associations or foundations of the financial situation, of the annual accounts and of the regularity, according to the Code for Companies and Associations (CCA), and the statutes or articles of association, of the transactions reflected in the annual accounts, must be assigned to one or more statutory auditors if:

• the company exceeds for 2 consecutive years on the balance sheet date more than 1 of the criteria set out in Art. 1:24 of the CCA concerning turnover, balance sheet total and FTE ( "large company", see: Size criteria for companies), aside from special rules that apply to certain specific categories of companies;

• the association or foundation exceeds for 2 consecutive years on the balance sheet date more than 1 of the criteria set out in Art. 1:28 CCA and Art. 1:30 CCA concerning turnover, balance sheet total and FTE ("large association or foundation", see: Size criteria for associations and foundations), aside from special rules that apply to certain specific categories of associations or foundations.

For companies, non-profit organizations, international non-profit organizations and foundations starting their business, for the application of the above criteria, these figures are estimated in good faith at the beginning of the financial year. If this estimate shows that at least two of the criteria will be exceeded during the first financial year, this must be taken into account immediately for that first financial year.

Small listed companies, small companies that are organizations of public interest and companies that are part of a group that must consolidate (Art. 141, 2° Companies Code / Art. 3:72, 2° CCA) are always obliged to appoint an auditor.