(a) Purpose. Section 4211 of ERISA provides four methods for allocating unfunded vested benefits to employers that withdraw from a multiemployer plan: the presumptive method (section 4211(b)); the modified presumptive method (section 4211(c)(2)); the rolling-5 method (section 4211(c)(3)); and the direct attribution method (section 4211(c)(4)). With the minor exceptions covered in §4211.3, a plan determines the amount of unfunded vested benefits allocable to a withdrawing employer in accordance with the presumptive method, unless the plan is amended to adopt an alternative allocative method. Generally, the PBGC must approve the adoption of an alternative allocation method. On September 25, 1984, 49 FR 37686, the PBGC granted a class approval of all plan amendments adopting one of the statutory alternative allocation methods. Subpart C sets forth the criteria and procedures for PBGC approval of nonstatutory alternative allocation methods. Section 4211(c)(5) of ERISA also permits certain modifications to the statutory allocation methods. The PBGC is to prescribe these modifications in a regulation, and plans may adopt them without PBGC approval. Subpart B contains the permissible modifications to the statutory methods. Plans may adopt other modifications subject to PBGC approval under subpart C. Finally, under section 4211(f) of ERISA, the PBGC is required to prescribe rules governing the application of the statutory allocation methods or modified methods by plans following merger of multiemployer plans. Subpart D sets forth alternative allocative methods to be used by merged plans. In addition, such plans may adopt any of the allocation methods or modifications described under subparts B and C in accordance with the rules under subparts B and C.

(b) Scope. This part applies to all multiemployer plans covered by title IV of ERISA.