An auditor is a person or a firm appointed by a company to execute an audit. To act as an auditor, a person should be certified by the regulatory authority of accounting and auditing or possess certain specified qualifications. Generally, to act as an external auditor of the company, a person should have a certificate of practice from the regulatory authority. Audit firms are generally required to obtain official authorisation, registration, or recognition from a competent authority. In Germany, this is granted by the Wirtschaftsprüferkammer (WPK) and requires that the firm be managed responsibly by certified auditors.