A defined benefit pension valuation converts a future stream of monthly retirement payments into a single dollar figure today by discounting each expected payment back to the present using an assumed interest rate and multiplying by the probability the retiree will be alive to collect it. Add up every discounted, survival-weighted payment from the first month of retirement through the end of the mortality table, and you have the present value of the pension. The result is highly sensitive to the assumptions used, which is why the same benefit can carry very different valuations depending on who is doing the math and why.
The Math Behind the Number
Every valuation rests on the time value of money: a dollar received years from now is worth less than a dollar today, because a dollar today can be invested and grow. The actuary takes each future year’s expected payment, reduces it by an assumed interest rate (the discount rate), then reduces it again by the probability the participant survives to receive it. The present value of a payment at age 65 is higher than the present value of a payment at age 85, both because it arrives sooner and because survival to 65 is more likely than survival to 85.
A single-payment example makes the mechanic concrete. If the discount rate is 5% and a $50,000 payment arrives in five years, the present value of that payment is roughly $50,000 รท (1.05)^5, or about $39,176. The actuary multiplies that by the probability the participant survives to collect it, then repeats the exercise for every year of expected payments and sums the results. That total is the lump-sum present value.
Two levers dominate the answer: the discount rate and the mortality assumption. A handful of other assumptions fine-tune it.
The Discount Rate
The discount rate moves the needle more than any other input. A higher rate shrinks the present value, because each dollar is assumed to grow faster between now and the payment date, so fewer dollars are needed today to replicate the future stream. A lower rate inflates the lump-sum figure.
The effect is not subtle. When interest rates rose sharply in 2022 and 2023, lump-sum offers dropped by tens of thousands of dollars even though the underlying monthly benefit had not changed. To put numbers on it, a $5,000 monthly pension discounted at 4% might produce a lump sum near $815,000, while the same benefit discounted at 6% drops to roughly $688,000, a difference of about $127,000.
Which rate applies depends on the purpose of the valuation. The IRS publishes segment rates each month, derived from a corporate bond yield curve, that plans use to calculate lump-sum equivalents. For February 2026, those adjusted rates were 4.75% for the first segment, 5.25% for the second, and 5.78% for the third, each covering a different time horizon of future payments.1Internal Revenue Service. Pension Plan Funding Segment Rates For regulatory funding purposes, Congress has prescribed the specific yield curve that the IRS publishes and updates monthly.2Office of the Law Revision Counsel. 26 USC 430 – Minimum Funding Standards for Single-Employer Defined Benefit Pension Plans For corporate financial reporting, the discount rate is pegged to yields on high-quality corporate bonds with maturities matching expected payment timing. For estate tax valuations, the IRS uses a completely different rate tied to 120% of the federal midterm rate.
Most plans lock in a single month’s segment rates for an entire year of lump-sum calculations. If you know which month your plan uses as its lookback month, you can track the IRS segment rate tables to anticipate whether next year’s offer will be higher or lower than this year’s.
Mortality and Longevity
The second major input is how long the participant is expected to live, because that determines how many payments the plan expects to make. Actuaries use published mortality tables that assign a probability of death and survival at every age. Without them, there is no way to estimate the total cost of a lifetime income promise.
For regulatory funding calculations, the IRS prescribes specific static mortality tables that plans must use. These are updated annually; the 2026 versions apply to all valuation dates occurring during the 2026 calendar year.3Internal Revenue Service. IRS Notice 25-40 – Updated Static Mortality Tables for Defined Benefit Pension Plans The tables reflect improvements in life expectancy over time, which generally makes the same pension more expensive to fund with each update.
When the PBGC takes over a terminated plan, it uses a different set of mortality assumptions under its ERISA Section 4044 regulations, including separate tables for healthy participants and participants receiving disability benefits.4eCFR. 29 CFR 4044.53 – Mortality Assumptions A participant who qualifies as Social Security disabled is valued using a dedicated disabled-lives mortality table that accounts for the shorter expected payment period.
Other Assumptions That Change the Result
Assumed Retirement Age
The actuary must estimate when the participant will start collecting. An earlier assumed retirement age means payments begin sooner and last longer, which increases the present value. A shift of even one year in the assumed average retirement age can change the calculated liability by several percentage points. Most actuaries base this estimate on the plan’s historical experience, but it remains a judgment call, especially for plans where many participants take early retirement.
Projected Salary Growth
Many defined benefit formulas tie the pension to final average salary, so the actuary must project pay increases between now and retirement. The projection typically combines a long-term inflation assumption with a component for merit raises and promotions. The combined assumption commonly falls in the range of 3% to 4.5% per year, though it varies by employer and industry. A higher salary growth assumption produces a larger projected final benefit and therefore a higher present value.
Cost-of-Living Adjustments
If the plan includes automatic post-retirement increases, the valuation must reflect them. A pension with a 3% annual cost-of-living increase is worth substantially more than a flat pension, because each year’s payment is larger than the last. Ignoring a cost-of-living feature can understate the true present value by 25% or more. If you are evaluating a lump-sum offer, check whether it reflects the full value of any cost-of-living provision the benefit carries.
Why the Same Pension Produces Different Valuations
Because the discount rate and mortality assumptions are dictated by the purpose of the calculation, one benefit can produce several defensible numbers at the same moment in time.
Corporate Financial Reporting
Companies that sponsor defined benefit plans must report the plan’s funded status on their balance sheet. The primary liability measure is the Projected Benefit Obligation, or PBO, the present value of all benefits employees have earned to date including an assumption about future salary increases.5FASB. Summary of Statement No. 158 Because the PBO bakes in expected raises, it produces the largest liability number and drives balance sheet reporting. A secondary measure, the Accumulated Benefit Obligation, uses the same methodology but freezes salaries at current levels; it answers a narrower question about what the plan would owe if every employee stopped working today. The gap between the two can be significant for plans covering a young workforce with steep expected salary growth.
Regulatory Funding
The financial reporting valuation tells investors what the plan owes. The regulatory funding valuation tells the employer how much cash to put in. Under the Internal Revenue Code, single-employer defined benefit plans must maintain a funding target equal to the present value of all benefits accrued as of the valuation date, calculated using the IRS-prescribed corporate bond yield curve and mortality tables.2Office of the Law Revision Counsel. 26 USC 430 – Minimum Funding Standards for Single-Employer Defined Benefit Pension Plans If assets fall short, the employer must contribute enough to close the gap over a statutory amortization period. Failure to meet the minimum required contribution triggers an IRS excise tax equal to 10% of the unpaid amount for each year the shortfall persists, with additional penalties if the underfunding is not corrected.6Office of the Law Revision Counsel. 26 USC 4971 – Taxes on Failure to Meet Minimum Funding Standards>
Estate Tax
When a participant dies and the benefit passes to a beneficiary or estate, the present value of remaining payments must be included in the decedent’s gross estate. The IRS requires this calculation to use the Section 7520 interest rate, which equals 120% of the federal midterm rate rounded to the nearest two-tenths of a percent.7Office of the Law Revision Counsel. 26 USC 7520 – Valuation Tables For March 2026, that rate is 4.8%.8Internal Revenue Service. Section 7520 Interest Rates The rate is paired with IRS-prescribed mortality tables under the Treasury Regulations to produce a standardized present value.9eCFR. 26 CFR 20.7520-1 – Valuation of Annuities, Unitrust Interests, Interests for Life or Term of Years, and Remainder or Reversionary Interests This eliminates the subjectivity present in other contexts; every estate uses the same rate and tables for a given month. If the estate qualifies, the executor can elect to use the Section 7520 rate from either of the two months preceding the valuation date if it produces a more favorable result.
Divorce
A defined benefit pension earned during a marriage is typically treated as marital property. Courts use one of two approaches. In a present-value offset, an actuary calculates the lump-sum value of the marital portion of the pension as of the divorce date, and the non-employee spouse receives that value through other assets while the employee spouse keeps the pension intact. This requires agreeing on a discount rate and mortality table, and that is often where disputes arise; a slightly higher discount rate benefits the employee spouse by shrinking the calculated value. The second approach defers the split with a Qualified Domestic Relations Order that directs the plan administrator to pay the non-employee spouse a specified share of each monthly payment once benefits begin. No actuarial valuation is needed at the time of divorce, which avoids arguments over assumptions and shifts investment and mortality risk to both spouses equally. Professional fees for drafting a QDRO and performing the underlying analysis typically range from a few hundred to a couple thousand dollars, depending on plan complexity.
PBGC Takeover
When the PBGC takes over a terminated plan, it uses its own interest rate assumptions, derived from a yield curve based on Treasury rates with specific adjustments, rather than the segment rates the plan used while active.10Pension Benefit Guaranty Corporation. ERISA 4044 Interest Assumption The PBGC’s assumptions can produce a different present value than the plan itself would have calculated.
The PBGC guarantee also caps what participants can rely on receiving. For plans terminating in 2026, the maximum monthly benefit guaranteed for a 65-year-old retiree taking a straight-life annuity is $7,789.77.11Pension Benefit Guaranty Corporation. Maximum Monthly Guarantee Tables That cap drops for earlier retirement (a 55-year-old’s maximum is only $3,505.40 per month) and rises for older ages. If your pension exceeds the guarantee and the plan is at risk of termination, the guaranteed amount is the practical ceiling on what you can count on, and that should factor into any valuation of the annuity alternative.
What the Valuation Means for a Lump-Sum Decision
For many participants, the reason to understand valuation is to evaluate a lump-sum-versus-annuity choice. The lump-sum offer is the plan’s estimate of what the pension is worth in today’s dollars, but whether taking it is a good deal depends on personal circumstances.
The annuity wins if you live a long time. Payments continue for life, and every year past the plan’s breakeven point is money you would not have had if you took the lump sum and spent it down. If your health is good and longevity runs in your family, the annuity carries less risk.
The lump sum wins if you die earlier than average, if you can invest the money and earn returns above the discount rate baked into the offer, or if flexibility matters to you. A lump sum can be rolled into an IRA, invested to keep pace with inflation, and passed to heirs. None of that is possible with a standard life annuity. It also removes your dependence on the financial health of the plan sponsor.
The variables that matter most are your life expectancy, your comfort with investment risk, whether you have other reliable income like Social Security, and whether the pension carries a cost-of-living adjustment. A pension with built-in inflation protection is worth more as an annuity than one with flat payments, because the lump-sum offer may not fully reflect the compounding value of those annual increases. And because segment rates change monthly and drive lump-sum sizes, timing your retirement around a favorable rate environment is one of the few levers you have to influence the size of a payout.
Who Is Qualified to Do the Calculation
For regulatory funding purposes, the valuation must be signed by an Enrolled Actuary, a professional specifically licensed to certify pension calculations under ERISA. Enrollment is administered by the Joint Board for the Enrollment of Actuaries, a federal body, and requires passing examinations in both general actuarial methods and pension-specific actuarial knowledge, plus at least 36 months of responsible pension actuarial experience.12eCFR. Eligibility for Enrollment of Actuaries
For divorce valuations and personal planning estimates, you do not need an Enrolled Actuary; any qualified actuary or pension valuation specialist can run the numbers. If you are challenging a plan’s funding valuation or need a figure that will hold up in court, the credential of the person behind the calculation matters. An Enrolled Actuary’s signature carries legal weight that a financial planner’s spreadsheet does not.
Challenging a Valuation You Believe Is Wrong
If you believe your benefit was calculated incorrectly (wrong service credit, wrong salary data, wrong formula), federal law gives you a structured process to challenge it. Every plan covered by ERISA must maintain a claims procedure that allows appeal of an adverse benefit determination.13eCFR. 29 CFR 2560.503-1 – Claims Procedure You generally have at least 60 days after receiving a denial to file your appeal. During the review, you can submit written arguments, supporting documents, and any other evidence you believe is relevant, and the plan must consider everything submitted, even materials that were not part of the original determination. The plan administrator then has 60 days to issue a decision, with a possible 60-day extension if special circumstances require it.
If the plan denies your appeal, or if it fails to follow its own claims procedures, you have the right to bring a civil action in federal or state court to recover benefits owed.14Office of the Law Revision Counsel. 29 USC 1132 – Civil Enforcement Courts hear these cases without a minimum dollar threshold. Hiring an independent actuary to review your benefit calculation before filing suit is often the most cost-effective first step, because errors are frequently data-entry mistakes (wrong hire date, missing overtime, incorrect break-in-service calculations) rather than disputes over actuarial methodology.