29 U.S.C. § 1364 — Liability on termination of single-employer plans under multiple controlled groups

(a) This section applies to every contributing sponsor of a single-employer plan that has at least two contributing sponsors, when at least two of them are not under common control when the plan ends under section 1341(c) or 1342 of this title, or when they contributed under the plan at any time during the five plan years before termination. This section does not define “contributing sponsor,“ “single-employer plan,“ “common control,“ or “plan year^*.“ (b) The corporation must determine the liability of each contributing sponsor and each member of its controlled group consistently with section 1362 of this title. However, the amount for the entire plan determined under section 1362(b)(1) must be allocated to each controlled group by multiplying that amount by a fraction. (1) The fraction's numerator is the amount that persons in that controlled group, as contributing sponsors, were required to contribute for the last five plan years ending before termination. (2) The denominator is the total amount that all persons, as contributing sponsors, were required to contribute for those five plan years. Section 1368(a) of this title applies separately to each controlled group. The corporation may also determine each contributing sponsor's and controlled-group member's liability on any other equitable basis that the corporation prescribes by regulation.