Act, in taxable years ending after the last day of such period, and (2) the amendments made by sections 3 and 4 shall apply to derivatives and underlying investments held after the last day of such period. (b) Identification requirements If, as of the close of the 90-day period described in subsection (a)(1), a taxpayer simultaneously holds 1 or more derivatives with respect to an underlying investment and the underlying investment— (1) the taxpayer shall make the identifications required under section 492(c)(2) of Internal Revenue Code of 1986 (as added by section 2 of this Act) before the close of such period, and (2) if such identifications result in an investment hedging unit, the first applicable hedging period with respect to such unit shall begin on the day after the close of such period. (c) Definitions For purposes of this section, any term used in this section which is also used in part IV of subchapter E of chapter 1 of such Code (as so added) shall have the same meaning as when used in such part.