the Board may conduct an investigation of any act or practice, or omission to act, by a registered public accounting firm, any associated person of such firm, or both, that may violate any provision of this Act, the rules of the Board, the provisions of the securities laws relating to the preparation and issuance of audit reports and the obligations and liabilities of account- ants with respect thereto, including the rules of the Commission issued under this Act, or professional standards, regardless of how the act, practice, or omission is brought to the attention of the Board