29 CFR §4064.1

1. (a)Part 4062, subpart A, of this chapter sets forth rules for determination and payment of the liability incurred under section 4062(b) of ERISA, upon termination of any single-employer plan and, to the extent appropriate, determination of the liability incurred with respect to multiple employer plans under sections 4063 and 4064 of ERISA.
2. (b)Part 4068 of this chapter includes rules regarding the PBGC's lien under section 4068 of ERISA with respect to liability arising under section 4062, 4063, or 4064.