(a) The Public Utilities Regulatory Authority or any director or any hearing officer thereof may exercise the powers provided under subsection (a) of § 16-8, in relation to summoning and examining under oath, such witness and the production and examination of such books, records, vouchers, memoranda, documents, letters, contracts or other papers as it deems advisable of any holding company or subsidiary that is related to a public service company, provided such powers may be exercised in regard to (1) a holding company, only with respect to transactions between the holding company and a related public service company or transactions between the holding company and a subsidiary of such holding company which is not itself a public service company, which transactions are of the same type as transactions between such holding company and a related public service company, or (2) a subsidiary, only with respect to transactions between such subsidiary and a related public service company, and in either case only after having first determined that the exercise of such powers may be necessary to protect customers of the related public service company from any adverse impact on the costs, revenues, rates, charges or quality of service of such public service company.

(b) The authority may require the audit of (1) transactions between a public service company and a related holding company or subsidiary which is not itself a public service company, and (2) transactions between a related holding company and a subsidiary of such holding company which is not itself a public service company, which transactions are of the same type as transactions between such holding company and a related public service company, to the extent necessary to ensure that such transactions do not have an adverse impact on the costs or revenues of the public service company, the rates and charges paid by the customers of the public service company or upon the quality of service of such public service company. Upon completion of any audit conducted pursuant to this section, if the authority determines that any transactions which were the subject of such audit have had an adverse impact on the costs, revenues, rates, charges or quality of service of the public service company, the authority may exercise its powers under this title with respect to the public service company to ensure that the rates, charges and quality of service of the public service company conform to the principles and guidelines set forth in § 16-19e. The authority may disallow, for rate-making purposes, the costs of the audit, after first considering the reasons for the audit and any adverse impact on the customers of the public service company.

(c) Proprietary commercial and proprietary financial information of a holding company or subsidiary provided pursuant to this section shall be confidential and protected by the authority, subject to the provisions of § 4-177.

(d) For the purposes of this section, a subsidiary and a public service company are related if the subsidiary is owned or controlled by the public service company, a holding company thereof, a subsidiary of the public service company or holding company, or a subsidiary of such subsidiary. A holding company and a public service company are related if the public service company is owned or controlled by the holding company, a subsidiary of such holding company or a subsidiary of such subsidiary.

(e) As used in this section, (1) “holding company” means a company as defined in § 16-47, (2) “controlled” or “control” means the possession of the power to direct or cause the direction of the management and policies of a public service company, a holding company, or a subsidiary whether through the ownership of its voting securities, the ability to effect a change in the composition of its board of directors or otherwise, (3) “subsidiary” means any corporation, limited liability company, company, association, joint stock association, partnership, person or other entity which is owned or controlled, directly or indirectly, by a public service company, a holding company or a subsidiary of a public service company or holding company, and (4) “transactions” means cost allocations, capital structure, provision of goods and services, transfers of assets and liabilities, loans, financings, leases and other financial obligations.

(f) Nothing in this section shall be deemed to limit any existing statutory powers of the authority with respect to public service companies, holding companies or subsidiaries.

(g) The authority may conduct joint hearings with another agency including, but not limited to, the utility regulatory agency of another state on matters of mutual cognizance and interest.