29 C.F.R. § 4044.52

The plan administrator shall value all benefits as of the valuation date by—

(a) Using the mortality assumptions prescribed by § 4044.53 and the interest assumptions prescribed by § 4044.54;

(b) Using interpolation methods, where necessary, at least as accurate as linear interpolation;

(c) Using valuation formulas that accord with generally accepted actuarial principles and practices; and

(d) Adding an expense loading charge determined in accordance with this paragraph (d) to the total value of benefits.

(1) Expense loading charge. The expense loading charge equals the sum of—

(i) Four hundred dollars ($400) multiplied by the applicable inflation multiplier determined in accordance with paragraph (d)(2) of this section and rounded to the nearest dollar, multiplied by the lesser of the participant count and 100, and

(ii) Two hundred-fifty dollars ($250) multiplied by the applicable inflation multiplier determined in accordance with paragraph (d)(2) of this section and rounded to the nearest dollar, multiplied by the excess, if any, of the participant count over 100.

(2) Applicable inflation multiplier. Except as provided in the next sentence, the applicable inflation multiplier equals the value of the CPI-U for September of the year preceding the year containing the valuation date divided by 296.808 (the value of the CPI-U for September of 2022), but not less than 1. However, for a valuation date on any day in January except the 31st, the applicable inflation multiplier is determined as if the valuation date were December 31 of the year preceding the year containing the valuation date. The term “CPI-U” means the Consumer Price Index for All Urban Consumers, not seasonally adjusted as published by the Bureau of Labor Statistics of the Department of Labor.