Updated test period
(2) Updated test period. The test period begins again with the beginning of the first taxable year after the close of a qualifying period (as defined in paragraph (d)(4)(ii)(C) of this section). This new test period, the updated test period, is the three taxable-year period beginning with the first taxable year after the close of the qualifying period. (C) Qualifying period(1) In general. A qualifying period includes each of the first five taxable years beginning with the first taxable year after a test period (or updated test period).