(or employers) maintaining the plan extending beyond the close of the earlier of— (i) the period permitted under section 410(a)(1) (determined without regard to subparagraph (B)(i) thereof), or (ii) subject to the provisions of paragraph (14), the first period of 3 consecutive 12-month periods during each of which the employee has at least 500 hours of service. . (2) Special rules Section 401(k) of the Internal Revenue Code of 1986 is amended by adding at the end the following new paragraph: (15) Special rules for participation requirement for long-term, part-time workers For purposes of paragraph (2)(D)(ii)— (A) Age requirement must be met Paragraph (2)(D)(ii) shall not apply to an employee unless the employee has met the requirement of section 410(a)(1)(A)(i) by the close of the last of the 12-month periods described in such paragraph. (B) Nondiscrimination and top-heavy rules not to apply (i) Nondiscrimination rules In the case of employees who are eligible to participate in the arrangement solely by reason of paragraph (2)(D)(ii)— (I) notwithstanding subsection (a)(4), an employer shall not be required to make nonelective or matching contributions on behalf of such employees even if such contributions are made on behalf of other employees eligible to participate in the arrangement, and (II) an employer may elect to exclude such employees from the application of subsection (a)(4), paragraph (3), subsection (m)(2), and section 410(b). (ii) Top-heavy rules An employer may elect to exclude all employees who are eligible to participate in a plan maintained by the employer solely by reason of paragraph (2)(D)(ii) from the application of the vesting and benefit requirements under subsections (b) and (c) of section 416. (iii) Vesting For purposes of determining whether an employee described in clause (i) has a nonforfeitable right to employer contributions (other than contributions described in paragraph (3)(D)(i)) under the arrangement, each 12-month period for which the employee has at least 500 hours of service