Actuarial Valuation of Pensions: Methods, Assumptions, and Present Value

An actuarial valuation of pensions is the annual calculation that translates a defined benefit plan’s long-term promises into a dollar figure the sponsor must fund today. The actuary projects every future benefit payment the plan is expected to make, discounts those payments to present value, compares the result against the plan’s assets, and produces the minimum contribution the employer owes for the year. Federal law requires this exercise every year for single-employer defined benefit plans, and the outputs drive employer contributions, PBGC premiums, participant disclosures, and in some cases direct restrictions on the benefits participants can receive.

What the Valuation Actually Determines

Internal Revenue Code Section 430 supplies the funding math for single-employer defined benefit plans. When plan assets fall below the funding target, the minimum required contribution equals the plan’s target normal cost plus a shortfall amortization charge. When assets meet or exceed the funding target, the employer only owes the target normal cost, reduced by the surplus.¹

Section 430 also fixes when the calculation happens. All funding determinations are made as of the plan’s valuation date, which for most plans is the first day of the plan year. Plans with 100 or fewer participants on every day of the prior year get flexibility and may designate any day during the plan year as their valuation date.² ERISA sets the broader framework, requiring plan sponsors to meet minimum standards for funding, vesting, and benefit accrual.³

The Data and Assumptions That Feed the Calculation

Census Data on Every Participant

Every valuation starts with participant records. Plan administrators compile date-of-birth, hire date, salary history, vesting status, and benefit election information for each active worker, deferred vested participant, and retiree currently in pay status. Errors ripple through the entire calculation. Overstated salaries inflate the projected benefit and produce a larger liability than the plan actually owes; understated records suppress the liability, so the plan may not collect enough contributions and can face excise taxes for underfunding.

Auditors verify census data against personnel files, payroll records, and enrollment forms. They confirm that every enrolled employee is actually eligible, that reported compensation matches payroll, and that terminated employees carry the correct separation date. Data quality is the single biggest factor an actuary cannot fix through modeling. Sophisticated assumptions layered on bad data just produce a precisely wrong answer.

Demographic Assumptions

Actuaries layer demographic projections onto the census to model when and how long benefits will be paid. Mortality tables estimate how long participants will live after retirement, directly controlling the number of expected payments. The IRS publishes updated static mortality tables that plans must use for minimum funding, and the methodology for the 2026 plan year builds on base mortality rates and mortality improvement rates specified in Treasury regulations.⁴ The Society of Actuaries monitors emerging longevity trends and publishes research that informs how those tables evolve.⁵

Beyond mortality, actuaries project expected retirement ages, rates of employee turnover, and the likelihood of disability. A workforce that tends to retire early starts drawing benefits sooner and accumulates more total payments than one that works to 65. High turnover, meanwhile, reduces long-term liability because many employees leave before earning a substantial benefit.

Economic Assumptions

Economic assumptions capture what happens to salaries and prices between hire and retirement. Expected salary growth matters enormously for plans that base benefits on final average pay. A 1% difference in annual wage growth compounds into a much larger projected benefit over a 30-year career. Plans offering cost-of-living adjustments to retirees must also project inflation, since those adjustments raise payments every year after retirement. Overestimating growth produces unnecessarily high contributions; underestimating it builds an underfunding surprise that surfaces only as employees approach retirement.

How the Cost of Benefits Is Allocated Across Years

An actuarial cost method is the formula that assigns the total cost of a pension benefit to specific years of service. The choice affects how contributions are spread across a worker’s career and how the plan’s liability appears on financial statements.

Entry Age Normal

The Entry Age Normal (EAN) method calculates the cost of each participant’s projected benefit as a level percentage of pay from hire date to assumed retirement. The portion of projected benefits allocated to a single valuation year is the “normal cost,” and any gap between the total liability and the present value of future normal costs is the “actuarial accrued liability.”⁶ EAN produces stable, predictable contribution patterns because it front-loads cost somewhat, avoiding the sharp increases that hit as a workforce ages. Section 430 effectively requires EAN for computing the funding target of single-employer plans.¹

Projected Unit Credit

The Projected Unit Credit (PUC) method treats each year of service as producing a separate “unit” of benefit. The actuary values only the benefit earned through the valuation date but uses projected future salary to size that benefit for final-average-pay plans. PUC produces lower costs in the early years of a career and higher costs later, because the benefit unit becomes more expensive to fund as retirement draws closer. FASB’s Accounting Standards Codification Topic 715 requires PUC for measuring pension obligations in financial statements, making it the standard for corporate accounting even though it is not the method used for IRS funding calculations. A company may therefore report a larger pension obligation on its balance sheet under PUC than it computes under the EAN-based funding target.

Discounting Future Benefits to Present Value

Present value is the bridge between a promise stretching decades into the future and a dollar amount the plan must hold today. For each projected monthly check, the actuary discounts it to today’s dollars using an assumed rate of return. A $1,000 payment due 20 years from now is worth considerably less than $1,000 today, because money invested now will grow over those 20 years. The higher the discount rate, the less a plan needs to set aside; the lower the rate, the more it needs.

Segment Rates

For IRS minimum funding purposes, plans do not pick their own discount rate. Section 430 prescribes three “segment rates” derived from yields on high-quality corporate bonds. Each segment covers a different time horizon of expected benefit payments, and the rates are averaged over a 24-month period to smooth short-term volatility.⁷ A sudden spike or drop in bond markets therefore does not immediately translate into a corresponding jolt in required contributions.

The Infrastructure Investment and Jobs Act of 2021 extended interest rate stabilization provisions that widen the corridor around these 24-month averages, keeping rates closer to a 25-year historical average.⁸ Without stabilization, a sustained low-rate environment would inflate present-value liabilities and force contribution increases that may not reflect the plan’s true long-term cost.

Sensitivity to Rate Changes

Even a modest shift in the discount rate can move a plan’s reported liability by millions of dollars. A drop of half a percentage point might push a plan from a comfortable surplus into a deficit, triggering higher required contributions and potentially benefit restrictions. Anyone reading a valuation report needs to understand that the funded status shown on paper can change significantly between valuation dates without a single participant retiring or a single dollar of benefits being paid.

Valuing the Plan’s Assets

The other half of the funded-status equation is what the plan actually owns. The fair market value of plan assets reflects the price at which stocks, bonds, and other holdings could be sold on the valuation date. That gives an accurate snapshot but can swing dramatically with markets, making year-to-year contribution planning difficult.

To smooth the volatility, plans may use an “actuarial value” of assets that phases in market gains and losses over several years rather than recognizing them all at once. Under current Treasury regulations, the actuarial asset value must stay within a corridor of 90% to 110% of fair market value.² A plan can bank part of a strong investment year as deferred gains that reduce future contributions gradually, but it cannot pretend a steep loss did not happen.

Once assets are valued, the actuary compares them to the present value of accrued liabilities. The resulting ratio is the plan’s funded percentage. A plan at 100% or above is fully funded. Below that, the gap represents the unfunded obligation, and the employer must close it through shortfall amortization installments.

What Happens When the Plan Is Underfunded

Shortfall Amortization

When assets fall short of the funding target, the employer amortizes the shortfall over 15 plan years in level annual installments, on top of paying the ongoing target normal cost. The amortization period was originally seven years; legislation effective for plan years beginning after December 31, 2021, extended it to 15 years, giving sponsors more time to close funding gaps without destabilizing cash flow.¹

Automatic Benefit Restrictions

Underfunding does not just raise contributions. It can directly limit what participants receive. IRC Section 436 imposes automatic restrictions based on the plan’s adjusted funding target attainment percentage (AFTAP):⁹

Below 60% funded, the plan cannot pay lump sums or other accelerated distributions, cannot pay shutdown or other unpredictable contingent event benefits, and must freeze all future benefit accruals.
Between 60% and 79% funded, lump-sum payments are capped at the lesser of 50% of the amount otherwise payable or the present value of the PBGC’s maximum guarantee for that participant. Plan amendments that increase liabilities are blocked.
At 80% or above, no automatic restrictions apply, though amendments that would drop the AFTAP below 80% are still prohibited.

If the plan sponsor is in bankruptcy, no lump sums or other accelerated payments can be made at all unless the actuary certifies that the AFTAP is at least 100%. These restrictions are not discretionary. They kick in automatically based on the certified AFTAP, which is why valuation results carry immediate consequences for participants.

Excise Taxes and PBGC Premiums

An employer that fails to make its minimum required contribution faces a 10% excise tax on the unpaid amount for single-employer plans. If the shortfall is not corrected by the end of the “taxable period,” the tax jumps to 100% of the unpaid balance.¹⁰

The Pension Benefit Guaranty Corporation adds a second cost. Every plan pays a flat-rate premium, set at $111 per participant for 2026 plan years, regardless of funded status.¹¹ Underfunded plans also pay a variable-rate premium of $52 for every $1,000 of unfunded vested benefits, subject to a per-participant cap of $751.¹² The variable premium is a direct financial incentive to improve funding, and for sponsors weighing whether to accelerate contributions, the premium savings often tip the analysis.

What Participants See From the Valuation

Valuations are not just an internal exercise. Federal regulations require plan administrators to share results with participants through an annual funding notice, provided within 120 days after the close of each plan year.¹³

The notice must include the plan’s funded percentage for the current year and the two preceding years, the total value of plan assets and liabilities, a breakdown of participants by status, a description of the plan’s investment policy and asset allocation, and a summary of any events that materially affected the plan’s financial position during the year.¹⁴ Plans must also include a general description of PBGC guarantee limits and information about how participants can request a copy of the plan’s annual report.

These disclosures give participants a window into whether their promised benefits sit on solid financial footing. A plan showing a declining funded percentage over three consecutive years is worth understanding closely, especially for participants nearing retirement who may be weighing a lump-sum election against the annuity option.

1
Office of the Law Revision Counsel. 26 USC 430 – Minimum Funding Standards for Single-Employer Defined Benefit Pension Plans
2
eCFR. 26 CFR 1.430(g)-1 – Valuation Date and Valuation of Plan Assets
3
U.S. Department of Labor. FAQs About Retirement Plans and ERISA
4
Internal Revenue Service. Updated Static Mortality Tables for Defined Benefit Pension Plans for 2026
5
Society of Actuaries. RPEC 2025 Mortality Improvement Update
6
Actuarial Standards Board. Entry Age Normal Actuarial Cost Method
7
Internal Revenue Service. Pension Plan Funding Segment Rates
8
U.S. Senate Committee on Commerce, Science, and Transportation. Bipartisan Infrastructure Investment and Jobs Act – Section by Section Summary
9
Office of the Law Revision Counsel. 26 USC 436 – Funding-Based Limits on Benefits and Benefit Accruals Under Single-Employer Plans
10
Office of the Law Revision Counsel. 26 USC 4971 – Taxes on Failure to Meet Minimum Funding Standards
11
Pension Benefit Guaranty Corporation. Premium Rates
12
Pension Benefit Guaranty Corporation. Comprehensive Premium Filing Instructions for 2026 Plan Years
13
U.S. Department of Labor. Field Assistance Bulletin No. 2025-02
14
eCFR. 29 CFR 2520.101-5 – Annual Funding Notice for Defined Benefit Pension Plans