Description: This is the fourth paper on n-year roll forward reserve financing of public benefit systems, especially Old-Age, Survivors and disability Insurance OASDI, prepared by University of Michigan faculty and students. As the papers have developed, some ideas have been simplified, while others have become more complex. It is concluded that the theoretical model requires further attention. This research can be extended to expand our knowledge of OASDI financing and the applicability of n-year roll forward reserve financing.