The fluctuation of the fund's payout hinges on interest rates and the mortality rate, according to Benedict Koh, director of the MSc in Applied Finance Programme at Singapore Management University (SMU). The variability of the payouts that members will get from the age of 65 for the rest of their lives was discussed at an annual longevity conference held by SMU's Sim Kee Boon Institute for Financial Economics' Centre for Silver Security.