011-8 Wyo. Code R. § 8-4
(a) Each Department assessed car company shall submit an annual report to the Department on or before May 1 each year. The requested information shall include: complete ownership delineation; reporting marks; class of cars; the number of units per class of cars; the total Wyoming mileage and system mileage for the preceding calendar year as defined by this chapter; route information and travel times necessary to determine average daily mileage; year(s) built or year(s) of acquisition; historical or original cost and additions and betterment made to cars; amount included in original cost associated with items included in the additions and betterment; daily average number of cars idle; and supplemental documents as the Depatment requires.
(b) Any request for extension of the filing deadline with the department shall be submitted in writing prior to the statutory due date. Extensions shall not be granted for greater than fifteen (15) calendar days.
(c) Failure to file a reporting form, or an incomplete filing by a company shall require the Department to value the company using the Best Information Available requirements of W.S. 39-13-107(a)(iii), W.S. W.S. 39-13-103(b)(xvi)(C), and by the methods set forth in this chapter. The failure to report shall subject the company to the penalty provisions of W.S. W.S. W.S. 39-13-108(c)(ii)(B).
(d) The Department shall notify each car company by October 15th of each year, the month to be used for the following year's time/speed study. If the company fails to provide the study, the Department shall used the best information available to determine the number of cars. The company shall be required to file the time/speed study every three years or upon Department request.
011-8 Wyo. Code R. § 8-4