29 CFR § 4044.41 - General valuation rules.
(a) Valuation of benefits -
(2) Non-trusteed plans. The plan administrator of a non-trusteed plan shall value plan benefits in accordance with §§ 4044.71 through 4044.75. If a plan is unable to satisfy all benefits assigned to priority categories 1 through 4 on the distribution date, the PBGC will place it into trusteeship and the plan administrator shall re-value the benefits in accordance with §§ 4044.51 through 4044.57.