According to the Auditing Act, an auditor can be left unappointed for a limited liability company, cooperative, general partnership or limited partnership if none or at most one of the following conditions were met in the previous financial year and the one immediately preceding it:

The balance sheet total came to more than EUR 100,000
Net sales or comparable revenues were more than EUR 200,000
The average number of employees was greater than three.

If a company engages in buying and managing securities and has significant control over the management of another organisation with a legal obligation to keep books (chapter 1, section 8 of the Accounting Act), it must appoint an auditor, even if it does not meet the conditions specified above.

The auditor appointed for a limited liability company, cooperative, general partnership or limited partnership must be a KHT or HT auditor or auditing firm. Publicly traded companies and organisations must always appoint a KHT auditor or auditing firm. Companies that meet two of the following conditions must also appoint a KHT auditor:

The balance sheet total is more than EUR 25 million
Net sales or comparable revenues are more than EUR 50 million
The average number of employees is greater than 300.

Even if the above provisions of the law do not require a company to appoint an auditor, its articles of association or partnership agreement may state otherwise. An auditor must be appointed if the articles of association so require.

A deputy auditor does not need to be appointed if a KHT or HT auditing firm is selected as auditor. However, each individual appointed as auditor must have an authorised deputy auditor or auditing firm.