Sales/use tax refund claim (quarterly filers): within 3 years from last day of month following the quarter of overpayment (latest of 6902 periods controls)

For persons required to file returns on other than an annual basis, except as provided in subdivision (b) no refund shall be approved by the board after three years from the last day of the month following the close of the quarterly period for which the overpayment was made, or, with respect to determinations made under Article 2 (commencing with Section 6481), Article 3 (commencing with Section 6511), or Article 4 (commencing with Section 6536) of Chapter 5 of this part, after six months from the date the determinations become final, or after six months from the date of overpayment, whichever period expires the later, unless a claim therefor is filed with the board within that period.

Gov. Code 6800: "The time in which any act provided by law is to be done is computed by excluding the first day, and including the last, unless the last day is a holiday, and then it is also excluded." Gov. Code 6707: "When the last day for filing any instrument or other document with a state agency falls upon a Saturday or holiday, such act may be performed upon the next business day with the same effect as if it had been performed upon the day appointed." 8 CCR 10600: "(a) The time in which any act provided by these rules is to be performed is computed by excluding the first day and including the last. (b) Unless otherwise provided by law, if the last day for exercising or performing any right or duty to act or respond falls on a weekend, or on a holiday for which the offices of the Workers' Compensation Appeals Board are closed, the act or response may be performed or exercised upon the next business day." 8 CCR 32130(a)-(b) (PERB): "(a) In computing any period of time under these regulations, except under Section 32776(c), (d), (e) and (f), the period of time begins to run the day after the act or occurrence referred to. (b) Whenever the last date to file a document falls on Saturday, Sunday, or a holiday, as defined in Government Code Sections 6700 and 6701, or PERB offices are closed, the time period for filing shall be extended to and include the next regular PERB business day. The extension of time provided herein shall be applied subsequent to the application of any other extension of time provided by these regulations or by other applicable law." CCP 12a(a): "If the last day for the performance of any act provided or required by law to be performed within a specified period of time is a holiday, then that period is hereby extended to and including the next day that is not a holiday. For purposes of this section, “holiday” means all day on Saturdays, all holidays specified in Section 135 and, to the extent provided in Section 12b, all days that by terms of Section 12b are required to be considered as holidays."