Title 26 › 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 › § 433
Each CSEC pension plan must keep a funding standard account and track whether charges to that account are bigger than credits. That shortfall is the "accumulated funding deficiency" (or, if smaller, it can be measured using an alternative minimum account). The account is charged with the plan’s normal cost and several amortized amounts: unfunded past service liability (amortized 40 years for plans that existed on Jan. 1, 1974, or 30 years for plans that started after that date but before the first plan year after Dec. 31, 2013), plan-amendment increases 15 years, experience losses 5 years, assumption-change losses 10 years, waived deficiencies 5 years, certain credits 5 years, and certain prior contributions 20 years. The account is credited by employer contributions and by amortized gains or decreases (15, 5, and 10 year rules). Interest is charged or credited at the plan’s interest rate, except certain amortizations must use at least 150% of the Federal mid-term rate, and underpayments are charged at least 175% of that rate. Plans must use reasonable actuarial methods, value assets on a fair-market basis allowed by the Secretary, and do valuations at least once a year. Contributions made within 8½ months after a plan year end count as if they were made on the last day of that year. Plans that meet certain tests can use an alternative minimum funding account with its own charge and credit rules. Plans with less than 100% funded current liability must pay required amounts in four quarterly installments due April 15, July 15, October 15, and January 15, each equal to 25% of the required annual payment (which is the lesser of 90% of the year’s required amount or 100% of last year’s). If unpaid amounts (with interest) exceed $1,000,000, a lien arises on the employer’s property and the employer must notify the PBGC within 10 days; the PBGC or a directed employer can enforce the lien. The law sets how to measure current liability (including using the third-segment interest rate and Secretary-set mortality tables reviewed at least every 5 years) and special rules for disabled lives. If a plan’s funded percentage is under 80%, it is in funding restoration status: the plan must follow a stricter shortfall test, cannot adopt benefit-increasing amendments that raise liabilities during that year, must create a written restoration plan within 180 days to reach 100% funding in no more than 7 years, and the plan actuary must certify status within 90 days of each plan year.
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Internal Revenue Code, Source: USLM XML via OLRC
Legislative History
Reference
Citation
26 U.S.C. § 433
Title 26, Internal Revenue Code
Last Updated
Sep 23, 2026
Release point: 119-110