Title 26 › Subtitle Subtitle A— Income Taxes › Chapter 1— NORMAL TAXES AND SURTAXES › Subchapter D— Deferred Compensation, Etc. › Part III— RULES RELATING TO MINIMUM FUNDING STANDARDS AND BENEFIT LIMITATIONS › Subpart A— Minimum Funding Standards for Pension Plans › § 431
Multiemployer pension plans (plans run jointly by a union and a group of employers) must keep a special bookkeeping ledger called a funding standard account to show they are putting enough money aside to pay promised benefits. Each year the account is charged with the plan's normal yearly cost, plus installments that pay down shortfalls over time. A plan that started on or after January 1, 2008 pays off its starting unfunded past liability in equal yearly installments over 15 plan years. Increases in liability from new benefit amendments, investment or experience losses, and losses from changing actuarial assumptions are each paid off over 15 plan years as well, and missed contributions the government waived are also spread over 15 plan years. If a benefit increase from an amendment is paid out over 14 years or less instead of as a lifetime annuity, that increase is spread over the shorter payout period instead of 15 years. The account is credited with the employer contributions actually made, plus matching 15-year installments for gains and liability decreases. If total charges ever exceed total credits, the plan has an accumulated funding deficiency, which triggers consequences under the funding rules. Money employers pay when they withdraw from the plan counts as contributions, while certain payments to the Pension Benefit Guaranty Corporation reduce the contributions counted. Amounts that were already being paid off under the older pre-2008 rules keep their old schedules. The numbers behind the account come from the plan's actuary. Assets must be valued using a reasonable method that takes fair market value into account, every assumption must be reasonable, and a full valuation of the plan's liabilities must be done at least once a year. A plan may use a valuation from the prior year only if its assets were at least 100 percent of its current liability, and it cannot switch to that approach unless assets were at least 125 percent of current liability. Contributions made up to two and a half months after the plan year ends still count for that year, and the IRS can stretch that grace period by up to six more months. There is also a ceiling: once a plan reaches its full-funding limitation, the remaining installment charges are treated as fully paid. That limitation generally cannot fall below the excess of 90 percent of the plan's current liability over the value of its assets, and the interest rate used to measure current liability must stay within a band of not more than 5 percent above and not more than 10 percent below the four-year weighted average of 30-year Treasury rates. Congress added two rounds of optional relief for plans that pass a solvency test, meaning the actuary certifies the plan can still pay expected benefits on time. First, plans could spread investment losses from the first two plan years ending after August 31, 2008 over up to 30 plan years instead of 15, and could smooth those losses in their asset values over up to 10 years, as long as the smoothed value stayed between 80 percent and 130 percent of fair market value. Second, a 2021 law let plans elect the same relief for losses tied to COVID-19, including drops in contributions and employment, by using February 29, 2020 in place of the 2008 date; under the session law, that election took effect as of the first plan year ending on or after February 29, 2020. A plan using this relief generally cannot put a benefit increase into effect during the next 2 plan years unless the increase is paid for with new contributions and the actuary certifies the plan's funding will not suffer, and the plan must notify participants and the Pension Benefit Guaranty Corporation. The 2008-era relief applies only to those long-past loss years, so today it mainly explains older amortization schedules still being paid off. Finally, a struggling plan can ask the IRS for more time. If the actuary certifies that the plan would otherwise run a funding deficiency in the current year or any of the 9 following plan years, has a funding improvement plan, can still pay benefits on time over the longer schedule, and has notified affected parties, the plan can apply to stretch out its amortization payments. The IRS may also grant an added discretionary extension of up to 10 years (reduced by any years already granted) if denying it would put the plan's survival or benefit levels at substantial risk and hurt participants overall, and it must act on such an application within 180 days.
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Internal Revenue Code — Source: USLM XML via OLRC
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Reference
Citation
26 U.S.C. § 431
Title 26 — Internal Revenue Code
Last Updated
Apr 6, 2026
Release point: 119-73