Ascertaining the extent of pension liabilities at any point in time is a critical erercise that must be undertaken at regular intervals. As contributions to employees' retirement saving accounts (RSAs) are expected to be made monthly, failure to comply by many employers has resulted to pension shortfalls that needs to be determined so that the beneficiaries ofdefined contribution (DC) scheme are not underpaid when they retire. Carrying out this exercise requires sound actuarial models that capture all funds not remitted as well as returns on expected contributions. Mixed method in terms of primary and secondary data were adoptedfor the study. The models developed in this study systematically account for all accruing benefits to employees in which their employers omitted to pay into their RSAs. Specifically. our findings revealed that out of550 employees from the selected institutions. 260 employees are being owed N191,687,720.46. Based on the pension shortfalls estimate, we concluded that the current members of DC with nofunds being remitted to their retirement saving accounts as and when due risk substantial pension wealth for as long as default continues. Consequently, we recommend that the National Pension Commission (NPC) should come to the aid of affected employees by making sure that employers take deliberate step to repay the estimated liabilities and other outstanding liabilities to their RSAs.