(at such time and in such manner as the Secretary may provide) the election under this subsection with respect to such stock. (C) Special rule for stock subject to lock-up periods (i) In general In the case of any qualified stock which is subject to a lock-up period— (I) such stock shall not be treated as transferable under subparagraph (B)(i), and (II) such stock shall not be treated as readily tradable on an established securities market under subparagraph (B)(iii), before the end of the lock-up period. (ii) Lock-up period For purposes of this subparagraph, the term lock-up period means any period (not to exceed 180 days)— (I) which begins on the date of an initial public offering, and (II) during which the qualified employee agrees, pursuant to an underwriting agreement entered into pursuant to such initial public offering, not to sell, otherwise dispose of, or hedge any qualified stock. (2) Qualified stock (A) In general For purposes of this subsection, the term qualified stock means, with respect to any qualified employee, any stock in a corporation which is the employer of such employee, if— (i) such stock is received— (I) in connection with the exercise of an option, or (II) in settlement of a restricted stock unit, and (ii) such option or restricted stock unit was granted by the corporation— (I) in connection with the performance of services as an employee, and (II) during a calendar year in which such corporation was an eligible corporation. (B) Limitation The term qualified stock shall not include any stock if the employee may sell such stock to, or otherwise receive cash in lieu of stock from, the corporation at the time that the rights of the employee in such stock first become transferable or not subject to a substantial risk of forfeiture. (C) Eligible corporation For purposes of subparagraph (A)(ii)(II)— (i) In general The term eligible corporation means, with respect to any calendar year, any corporation if— (I) no stock of such corporation (or any predecessor of such corporation) is readily