An off-balance sheet asset or liability created under FAS 87 rules when plan assets in a defined benefit pension plan exceed or fall short of the projected benefit obligation (PBO). The gain or loss is usually caused by actual investment returns for plan assets that exceed or fall short of expected or assumed rates of return. Gains or losses may also result from changes in actuarial assumptions. These are off-balance sheet assets or liabilities because volatile returns on plan assets realized in subsequent periods can reduce or completely offset the unrealized gains or losses that previously existed. These gains or losses are from changes in the plan or the plan assets that occur subsequent to the adoption of FAS 87 rules and should not be confused with initial transition assets, unrecognized transition assets, initial transition obligations, or unrecognized transition obligations. The amount of any unrecognized gains or losses is disclosed in a footnote to the financial statements.