Section 4(k) of the Bank Holding Company Act, 12 USC 1843(k), authorizes affiliations among banks, securities firms, insurance firms, and other financial companies. It provides for the formation of financial holding companies. A BHC that qualifies as a financial holding company may engage in activities that are financial in nature or incidental to a financial activity. Financial holding companies are authorized by statute to engage in designated financial activities, including insurance underwriting and agency activities, securities underwriting, merchant banking, and insurance company portfolio investment activities. In addition, financial holding companies may engage in those activities that the Board of Governors of the Federal Reserve System determines, in conjunction with the Secretary of the Treasury, to be financial in nature or incidental to a financial activity.