Section 831.117 - Computation of the supplemental liability(a) OPM will compute each supplemental liability of the Fund using demographic factors specific to the populations for which the supplemental liability applies.(b) The supplemental liability will be computed based on the economic assumptions used by the Board of Actuaries of the Civil Service Retirement System for the most recent valuation of the System.(c) Each supplemental liability shall be rounded to the nearest one hundred million dollars.82 FR 49279, Oct. 25, 2017