Oregon Revised Statutes Utility Regulation § 757.135

(1) Except as provided in subsection (2) of this section, the accounts required under ORS 757.120 and 757.125 shall be closed annually on December 31 and a balance sheet of that date promptly taken therefrom. On or before a date prescribed by the Public Utility Commission by rule, such balance sheet, together with such other information as the commission shall prescribe, verified by an officer of the public utility, shall be filed with the commission.

(2) If a public utility maintains its accounts and records on a fiscal year basis, the accounts required by ORS 757.120 and 757.125 shall be closed annually on the last day of the fiscal year and a balance sheet shall be promptly taken from those accounts. On or before the first day of the fourth month following the end of the public utility's fiscal year, the balance sheet together with such information as the commission shall prescribe must be verified by an officer of the public utility and filed with the commission. The commission may require that a public utility filing information at the time specified in this subsection also file with the commission on a calendar year basis such additional information as may be prescribed by the commission.

(3) The commission may examine and audit any account. Items shall be allocated to the accounts in the manner prescribed by the commission.