Source: Jeffrey R. Brown, George Pennacchi, National Bureau of Economic Research (NBER), NBER Working Paper No. w21276, June 2015
From the abstract:
We argue that the appropriate discount rate for pension liabilities depends on the objective. In particular, if the objective is to measure pension under- or over- funding, a default-free discount rate should always be used, even if the liabilities are themselves not default-free. If, instead, the objective is to determine the market value of pension benefits, then it is appropriate that discount rates incorporate default risk. We also discuss the choice of a default-free discount rate. Finally, we show how cost-of-living adjustments (COLAs) that are common in public pensions can be accounted for and valued in this framework.