Given the need to ensure verification by independent experts, providers of very large online platforms and of very large online search engines should be accountable, through independent auditing, for their compliance with the obligations laid down by this Regulation and, where relevant, any complementary commitments undertaken pursuant to codes of conduct and crises protocols. In order to ensure that audits are carried out in an effective, efficient and timely manner, providers of very large online platforms and of very large online search engines should provide the necessary cooperation and assistance to the organisations carrying out the audits, including by giving the auditor access to all relevant data and premises necessary to perform the audit properly, including, where appropriate, to data related to algorithmic systems, and by answering oral or written questions. Auditors should also be able to make use of other sources of objective information, including studies by vetted researchers. Providers of very large online platforms and of very large online search engines should not undermine the performance of the audit. Audits should be performed according to best industry practices and high professional ethics and objectivity, with due regard, as appropriate, to auditing standards and codes of practice. Auditors should guarantee the confidentiality, security and integrity of the information, such as trade secrets, that they obtain when performing their tasks. This guarantee should not be a means to circumvent the applicability of audit obligations in this Regulation. Auditors should have the necessary expertise in the area of risk management and technical competence to audit algorithms. They should be independent, in order to be able to perform their tasks in an adequate and trustworthy manner. They should comply with core independence requirements for prohibited non-auditing services, firm rotation and non-contingent fees. If their independence and technical competence is not beyond doubt, they should resign or abstain from the audit engagement.
