FAS 87 pension accounting is the framework U.S. employers use to measure and report defined benefit pension obligations, now codified as ASC Topic 715 but built on the same core mechanics: recognize the full present value of pension promises on the balance sheet, and run an annual pension expense through the income statement that smooths out actuarial noise. The standard exists because defined benefit plans tie payouts to formulas involving years of service and future compensation, so the accounting has to project decades ahead using layered assumptions about discount rates, asset returns, employee turnover, and longevity.
What follows is how each piece of that framework works.
Measuring the Pension Obligation
The central liability measure is the Projected Benefit Obligation (PBO). The PBO is the present value of pension benefits employees have earned to date, calculated using expected future salary levels rather than current ones. That distinction is the whole point: most pension formulas base payouts on compensation near retirement, so ignoring future raises would significantly understate the real obligation. The PBO builds in estimates for inflation, productivity gains, seniority, and promotions.
A narrower measure, the Accumulated Benefit Obligation (ABO), performs the same present-value calculation using only current salary levels. The ABO answers a hypothetical: what would the obligation be if the plan froze today? The PBO is what drives the balance sheet liability and annual expense.
On the other side sit the plan assets, held in a legally separate trust and measured at fair value on the balance sheet date. The gap between the PBO and the fair value of plan assets is the plan’s funded status. Underfunded plans produce a liability; overfunded plans produce an asset.
The Three Assumptions That Move Everything
A handful of actuarial assumptions do most of the work, and small changes in any of them can shift the reported liability and annual expense significantly.
Discount Rate
The discount rate converts future benefit payments into today’s dollars. ASC 715 requires the rate to reference yields on high-quality fixed-income securities, and SEC staff guidance defines “high quality” as bonds rated AA or better by a major ratings agency. The maturity profile of those bonds should match the timing of expected benefit payments. On a large plan, a 50-basis-point drop in the discount rate can add hundreds of millions of dollars to the PBO, which makes this the single most consequential assumption on the page.
Expected Return on Plan Assets
The expected long-term rate of return reflects what the plan’s investment portfolio is anticipated to earn over time. It isn’t applied to the fair value of plan assets directly. Instead, ASC 715 permits a “market-related value” of plan assets, which can smooth changes in fair value over up to five years. The expected return, calculated against that smoothed value, offsets annual pension expense, so a higher assumption reduces reported cost. That creates an obvious incentive to be optimistic, which is why analysts watch this assumption closely. Different smoothing methods can be used for different asset classes, but no method may spread fair value changes over more than five years.
Mortality and Longevity
How long retirees are expected to live directly affects how much the plan will ultimately pay. The IRS publishes updated static mortality tables each year for use in pension liability calculations, developed from base mortality rates and mortality improvement projections in Treasury regulations.1Internal Revenue Service. Updated Static Mortality Tables for Defined Benefit Pension Plans for 2026 (Notice 2025-40) Plans can use generational tables, which project ongoing improvements in life expectancy year by year, or static tables that use a single snapshot. Small plans have the option to use the simpler static approach for funding calculations.
The Five Components of Net Periodic Pension Expense
The annual pension figure that hits the income statement is Net Periodic Pension Expense (NPPE), sometimes called net periodic pension cost. It is built from five components, and they do not all move in the same direction.
- Service cost is the increase in the PBO from employees earning one more year of benefits. It is the only component representing the current-period price of employee labor.
- Interest cost is the growth in the PBO from the passage of time. Because the obligation is measured at present value, it accretes interest each period at the discount rate, much like interest on a debt balance.
- Expected return on plan assets reduces NPPE. It applies the long-term expected return rate to the market-related value of plan assets at the start of the period. Using expected rather than actual returns is deliberate; it keeps market swings from whipsawing the income statement quarter to quarter.
- Amortization of prior service cost spreads the effect of retroactive benefit changes over the remaining service years of the employees who benefit from the change. If most participants are already retired, amortization runs over their remaining life expectancy instead.
- Amortization of net actuarial gains or losses handles the gap between assumptions and reality: discount rates that moved, mortality experience that diverged from the tables, asset returns above or below expectations. These gains and losses are initially parked in other comprehensive income and only enter NPPE under the corridor approach.
How the Corridor Smooths Gains and Losses
The corridor keeps actuarial volatility from slamming earnings each year. At the start of each year, compare the accumulated unrecognized net gain or loss sitting in other comprehensive income against a threshold equal to 10% of the greater of the PBO or the market-related value of plan assets. Anything inside the corridor requires no amortization. Only the excess is amortized, and even that is spread over the average remaining service period of active employees.
The consequence is a real delay between when economic gains or losses occur and when they affect reported earnings. A sharp market downturn might generate a large actuarial loss in year one that does not begin affecting pension expense until year two or three, and then only gradually. Companies may elect a faster amortization method, including immediate recognition of all gains and losses; the corridor is the minimum required.
Income Statement Presentation After ASU 2017-07
Before 2018, companies could lump all five components of NPPE together within operating expenses. ASU 2017-07 requires a split. Service cost must be presented with other employee compensation costs inside operating income. Every other component (interest cost, expected return on assets, amortization of prior service cost, amortization of gains and losses, and any settlement or curtailment charges) sits outside the operating income subtotal.2Financial Accounting Standards Board. Compensation – Retirement Benefits (Topic 715)
The presentation change carries a second effect. Only service cost is now eligible for capitalization into assets such as inventory or property; the other components cannot be capitalized.2Financial Accounting Standards Board. Compensation – Retirement Benefits (Topic 715) Operating income is the metric most analysts use to gauge core business performance, and pulling the financing-related and smoothing-related components below the operating line gives a cleaner read.
Balance Sheet Recognition and the Role of OCI
ASC 715 requires the balance sheet to reflect funded status directly. When the PBO exceeds plan assets, the company reports a pension liability. When plan assets exceed the PBO, it reports a pension asset. Companies with multiple plans must aggregate all overfunded plans into a single asset and all underfunded plans into a single liability. Netting an overfunded plan against an underfunded one is not permitted unless the employer has a clear right to shift assets between them.3Financial Accounting Standards Board. FASB EITF Issue Summary – Application of Topic 715 to Market-Return Cash Balance Plans
On a classified balance sheet, the pension liability splits into current and noncurrent portions. The current piece is the amount by which the present value of benefits payable in the next 12 months exceeds plan assets. Pension assets from overfunded plans are always classified as noncurrent.
Full recognition on the balance sheet creates real volatility. A drop in the discount rate inflates the PBO immediately. A bad year in equities shrinks plan assets immediately. Yet the income statement expense stays smoothed by the corridor and the expected-return mechanism. Other Comprehensive Income (OCI) is what bridges the two.
When an actuarial loss increases the PBO beyond what the smoothed expense captures, the difference lands in OCI. When a plan amendment increases benefits retroactively, the resulting prior service cost hits OCI immediately as well. These entries adjust stockholders’ equity through Accumulated Other Comprehensive Income (AOCI) without touching net income. Over time, amounts in AOCI migrate to the income statement through the amortization mechanisms already described. Pension-related AOCI therefore holds three categories: unamortized actuarial gains and losses, unamortized prior service costs or credits, and any remaining transition amounts from initial adoption of the standard. For companies with large, mature plans, that AOCI balance sometimes exceeds the pension liability itself.
Settlements and Curtailments
Normal pension accounting assumes the plan continues indefinitely. When that assumption breaks, ASC 715 requires special handling.
A settlement happens when the employer eliminates all or part of the pension obligation by transferring assets, typically through purchasing annuity contracts or paying lump sums to participants. Settlement accounting accelerates recognition of gains and losses previously deferred in AOCI. The proportion recognized equals the proportion of the PBO settled: settle 30% of the PBO and 30% of the accumulated unrecognized gain or loss flows into current-period earnings. There is a practical exception. Settlement accounting is not required if the total cost of all settlements during the year stays at or below the sum of service cost and interest cost for that year. A company may adopt a lower threshold, but whatever policy it chooses must be applied consistently.
A curtailment happens when a significant portion of future benefit accruals is eliminated, typically through a plant closing, workforce reduction, or plan freeze. Curtailment accounting accelerates recognition of prior service costs associated with service years that will no longer be rendered. If the curtailment also reduces the PBO, that reduction is a gain, offset against any accelerated prior service cost. When a settlement and curtailment happen together, as often occurs in a divestiture, the gains and losses from each are calculated separately and cannot be netted against each other.
Footnote Disclosures
The disclosure framework is designed to let investors assess pension risk independently rather than trust the summary numbers alone.
Companies must provide a reconciliation of the beginning and ending balances of both the PBO and the fair value of plan assets. The PBO reconciliation breaks out service cost, interest cost, actuarial gains and losses, plan amendments, and benefits paid. The asset reconciliation shows actual return on assets, employer contributions, participant contributions, benefits paid, and effects of business combinations or divestitures. Together, they let an analyst reconstruct exactly how funded status moved during the year.
A separate reconciliation connects funded status to the amounts recognized on the balance sheet, showing how deferred items in AOCI bridge the gap. NPPE components must be disclosed individually, which lets analysts isolate service cost from the financing and smoothing components sitting below the operating line.
Companies also disclose the key actuarial assumptions used to determine both the PBO and the annual expense: the discount rate, the expected long-term return on plan assets, and the expected rate of compensation increases. This is where the real analytical value lies. A company using an expected return on assets two percentage points above its peers is effectively flattering its earnings, and the disclosure makes it visible. A discount rate sitting above current market yields may indicate an understated PBO, and the disclosed rate lets an analyst recalculate. Sensitivity analyses showing how changes in the discount rate or expected return would affect the liability and expense are typical for companies with material obligations, and the footnotes often carry more decision-relevant content than the face of the statements.
A Note on ERISA and PBGC
ASC 715 accounting runs on a separate track from the legal funding requirements under ERISA and the Internal Revenue Code. Minimum contributions under IRC Section 430, quarterly installment schedules for underfunded plans, benefit-restriction thresholds tied to funding percentages, and PBGC premiums are cash and compliance obligations that do not directly determine pension expense or the balance sheet liability under GAAP.4Office of the Law Revision Counsel. 26 US Code 430 – Minimum Funding Standards for Single-Employer Defined Benefit Pension Plans5Pension Benefit Guaranty Corporation. Premium Rates They do, however, affect cash outflows that ultimately show up in the plan asset reconciliation as employer contributions, and any lien or benefit restriction triggered under ERISA becomes a disclosure matter of its own.