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 purposes of paragraph (2), a deemed election under this paragraph— (i) shall be treated as made as of the first time the taxpayer fails to meet the requirements of subsection (c) with respect to the underlying investment, and (ii) notwithstanding paragraph (2)(B), may be revoked with the consent of the Secretary. (c) Definitions and rules relating to taxpayers identifying investment hedging units In the case of a taxpayer with respect to which an election is not in effect under subsection (b) with respect to an underlying investment— (1) In general The taxpayer shall, at the times described in paragraph (3), test the derivatives with respect to the underlying investment and make the identifications described in paragraph (2). (2) Identification (A) In general The taxpayer shall identify the following with respect to an underlying investment: (i) Each derivative described in subsection (a)(1)(B)(i). (ii) The portions of the underlying investment described in subsection (a)(1)(B)(ii). (B) Derivatives and underlying investment not part of hedging unit A taxpayer shall identify the derivatives with respect to an underlying investment, and the portions of the underlying investment, which are not required to be identified under subparagraph (A). (C) Portion may include all of underlying investment For purposes of this part, the term portion with respect to any underlying investment identified may include all of the underlying investment. (3) Times identifications required to be made (A) In general The taxpayer shall test and make the identifications required under this subsection at the following times during any continuous period the taxpayer simultaneously holds 1 or more derivatives with respect to an underlying investment and 1 or more portions of the underlying