The appellants, Larrie Plymel and Corinne Monroe, are retired educators who are beneficiaries of the Teachers Retirement System of Georgia “TRS”. The appellees are the TRS and its Board of Trustees. This appeal concerns, among other things, whether the TRS properly calculated the appellants’ retirement benefits. The trial court granted summary judgment to the TRS and its Board, and denied partial summary judgment on liability to the appellants. For the reasons that follow, we reverse. 1. Appellant Plymel retired in 2002, and appellant Monroe retired in 1995. At retirement, the appellants had two options. They could have taken a maximum-plan allowance, which pays a fixed monthly benefit for the life of the retiree only.1 Instead of the maximum plan, the appellants took an optional-plan allowance, which pays a reduced allowance, first to the member during her life, and then to a person the member has named as a beneficiary after the member’s death.2 The appellants’ optional-plan retirement benefits were calculated using “option factors” adopted by the TRS in 1983. Option factors are a number less than one that is multiplied by what would have been a retiree’s monthly maximum-plan benefit to produce the retiree’s monthly optional-plan benefit. For example, if a maximum-plan payment for a retiree of a certain age is $1,000 per month, an optional-plan allowance might be calculated based on an optional factor of .70, thus requiring a payment of $700 per month over the course of the member’s life and the beneficiary’s life. The difference between the member’s maximum-plan payment and the reduced, optional-plan payment is used to purchase a life insurance vehicle to provide for the benefit of the member’s survivor. To create option factors, the TRS’s actuaries use a mortality table and an interest rate to calculate the present value of the maximum plan for a retiree of a certain age, and then, using that same table and interest rate, calculate an option factor that is designed to result in benefits payable to the member and her beneficiary that would equal the present value of the benefits under the maximum plan to the member only.
2. The dispute in this case arises from the requirement of OCGA § 47-3-121 a that an optional-plan allowance such as that chosen by the appellants must be actuarially equivalent to the maximum-plan allowance that the member could have chosen.3 In this regard, OCGA § 47-3-1 2 defines the term “actuarial equivalent” to mean “a benefit of equal value when computed at regular interest upon the basis of the mortality tables last adopted by the board of trustees.” The parties agree that, to determine if an optional-plan allowance is the actuarial equivalent of a maximum-plan allowance a member could have selected, the benefits payable under both allowances must be reduced to their present value using the same interest rate and mortality table. As the foregoing illustrates, to determine actuarial equivalence, one needs to know the “mortality tables last adopted by the board of trustees.”4 OCGA § 47-3-23 b is relevant to that inquiry. It provides as follows: b From time to time, but at least once in every five-year period, the actuary shall make an actuarial investigation into the mortality, service, and compensation experience of the members and beneficiaries of the retirement system and recommend for adoption by the board of trustees, mortality, service, and other tables needed in the operation of the retirement system. Taking into account the results of such investigations, the board of trustees from time to time shall adopt for the retirement system such mortality, service, and other tables as it shall deem necessary for use in all calculations required in connection with this retirement system. Pursuant to OCGA § 47-3-23 b, the TRS’s principal actuary conducted a review of the retirement system in 1982, 1986, 1992, 1996, and 2000, and the board of trustees adopted new mortality tables in those years based on the actuary’s recommendation.
