18 CFR 290.103 - Time of filing and reporting period.
All nonexempt electric utilities must file with any state regulatory authority having ratemaking authority for such utilities the information gathered pursuant to § 290.102, and all nonexempt, nonregulated electric utilities must make such information available to the public as follows:
(a) Biennial filing. Information required to be filed under § 290.102 must be filed biennially in even-numbered years on or before June 30 of that year.
(b) Reporting period. The reporting period is the calendar year immediately preceding the filing year. Information for previous years and projected information for future years must be reported on a calendar year basis.
(c) Alternate reporting period. Use of an alternate reporting period is permitted as follows:
(1) Except as provided in paragraph (c)(2) of this section, if a nonexempt electric utility has gathered all of the information specified in § 290.102 and has filed such information, based on a recent 12-month reporting period, either with its state regulatory authority or governing authority in connection with a retail rate proceeding, the nonexempt electric utility may substitute such information for the equivalent information required by this part in fulfillment of the biennial filing requirements.
(2) If a nonexempt electric utility not subject to the jurisdiction of a state regulatory authority maintains accounting records other than on a calendar year basis, such utility may use such other basis as the reporting period for purposes of compliance with this part, provided such reporting period is a 12-month period.