The purpose of this part is to establish rules for notifying the PBGC of the termination of a multiemployer plan and rules for the administration of multiemployer plans that have terminated by mass withdrawal. Subpart B prescribes the contents of and procedures for filing a Notice of Termination for a multiemployer plan. Subpart C prescribes basic duties of plan sponsors of mass-withdrawal-terminated plans. (Other duties are prescribed in part 4281 of this chapter.) Subpart D contains procedures for closing out sufficient plans. This part applies to terminated multiemployer plans covered by title IV of ERISA but, in the case of subparts C and D, only to plans terminated by mass withdrawal under section 4041A(a)(2) of ERISA (including plans created by partition pursuant to section 4233 of ERISA).