Ways in which pension obligation can be measured are:

• Accumulated Benefit Obligation (ABO): the present value of retirement benefits earned by employees, using current compensation levels.
• Vested Benefit Obligation (VBO): the portion of the accumulated benefit obligation that employees will receive regardless of their continued participation in the pension plan.
• Projected Benefit Obligation (PBO): the present value of retirement benefits earned by employees, using an estimate of future compensation levels.