Except as provided in paragraph (2), the amount of any contribution required by this section (including any required installments under paragraphs (3) and (4) of section 1083(j) of this title or under section 1085a(f) of this title) shall be paid by the employer responsible for making contributions to or under the plan.
Paragraph (1) shall not apply in the case of a multiemployer plan for any plan year in which the plan is in critical status pursuant to section 1085 of this title. This paragraph shall only apply if the plan sponsor adopts a rehabilitation plan in accordance with section 1085(e) of this title and complies with the terms of such rehabilitation plan (and any updates or modifications of the plan).
Except as provided in subparagraph (C), the Secretary of the Treasury may require an employer maintaining a defined benefit plan which is a single-employer plan (within the meaning of section 1301(a)(15) of this title) to provide security to such plan as a condition for granting or modifying a waiver under paragraph (1) or for granting an extension under section 1085a(d) of this title.
Any security provided under clause (i) may be perfected and enforced only by the Pension Benefit Guaranty Corporation, or at the direction of the Corporation, by a contributing sponsor (within the meaning of section 1301(a)(13) of this title), or a member of such sponsor’s controlled group (within the meaning of section 1301(a)(14) of this title).
The amount described in clause (i)(I) shall include any increase in such amount which would result if all applications for waivers or extensions with respect to the minimum funding standard under this subsection which are pending with respect to such plan were denied.
For purposes of subclause (I), any payment to or under a plan for any plan year shall be allocated first to unpaid minimum required contributions for all preceding plan years on a first-in, first-out basis and then to the minimum required contribution under section 1083 of this title for the plan year.
The Secretary of the Treasury shall, before granting a waiver under this subsection, require each applicant to provide evidence satisfactory to such Secretary that the applicant has provided notice of the filing of the application for such waiver to each affected party (as defined in section 1301(a)(21) of this title). Such notice shall include a description of the extent to which the plan is funded for benefits which are guaranteed under subchapter III and for benefit liabilities.
No amendment of a plan which increases the liabilities of the plan by reason of any increase in benefits, any change in the accrual of benefits, or any change in the rate at which benefits become nonforfeitable under the plan shall be adopted if a waiver under this subsection or an extension of time under section 1084(d) of this title or section 1085a(d) of this title is in effect with respect to the plan, or if a plan amendment described in subsection (d)(2) which reduces the accrued benefit of any participant has been made at any time in the preceding 12 months (24 months in the case of a multiemployer plan). If a plan is amended in violation of the preceding sentence, any such waiver, or extension of time, shall not apply to any plan year ending on or after the date on which such amendment is adopted.