with respect to any underlying investment of a taxpayer, a continuous period— (A) beginning with the first time (after a period which is not an applicable hedging period) the taxpayer holds 1 or more of the derivatives with respect to the underlying investment, and 1 or more portions of the underlying investment, which are described in paragraph (1)(B), and (B) ending with the time none of such derivatives and portions are so described. (3) Limitation on combination of derivatives in determining delta For purposes of paragraph (1)(B), the determination of which derivatives with respect to an underlying investment have a delta within the range described in paragraph (1)(B)(i), and the portion of the underlying investment with respect to which such derivatives have such delta, shall be made in the manner which results in the largest portion of such underlying investment being so described. (b) Election with respect to items included in investment hedging unit (1) In general A taxpayer may elect with respect to any underlying investment to treat for purposes of this part all derivatives with respect to such underlying investment, and all of such underlying investment, as part of an investment hedging unit. (2) Election Any election under this subsection with respect to an underlying investment— (A) shall apply to all derivatives with respect to the underlying investment, and all of the underlying investment, held at any time after the election is made (including during any period such derivatives or underlying investment are not held simultaneously), and (B) shall be irrevocable. (3) Deemed election for taxpayers failing to identify (A) In general If a taxpayer— (i) does not have an election in effect under paragraph (1) with respect to an underlying investment, and (ii) fails to meet the requirements of subsection (c) for testing and identifying derivatives with respect to the underlying investment, the taxpayer shall be treated as having made the election under paragraph (1). (B) Treatment of election For