(a) Use by plan actuary in determining unfunded vested benefits of a plan for computing withdrawal liability of employer The corporation may prescribe by regulation actuarial assumptions which may be used by a plan actuary in determining the unfunded vested benefits of a plan for purposes of determining an employer's withdrawal liability under this part. Withdrawal liability under this part shall be determined by each plan on the basis of—
(1) actuarial assumptions and methods which, in the aggregate, are reasonable (taking into account the experience of the plan and reasonable expectations) and which, in combination, offer the actuary's best estimate of anticipated experience under the plan, or
(2) actuarial assumptions and methods set forth in the corporation's regulations for purposes of determining an employer's withdrawal liability.
(b) Factors determinative of unfunded vested benefits of plan for computing withdrawal liability of employer In determining the unfunded vested benefits of a plan for purposes of determining an employer's withdrawal liability under this part, the plan actuary may—
(1) rely on the most recent complete actuarial valuation used for purposes of
section 412 of title 26 and reasonable estimates for the interim years of the unfunded vested benefits, and
(2) in the absence of complete data, rely on the data available or on data secured by a sampling which can reasonably be expected to be representative of the status of the entire plan.
(c) Determination of amount of unfunded vested benefits For purposes of this part, the term "unfunded vested benefits" means with respect to a plan, an amount equal to—
(A) the value of nonforfeitable benefits under the plan, less
(B) the value of the assets of the plan.
Source credit, amendments & notes
(Pub. L. 93–406, title IV, §4213, as added Pub. L. 96–364, title I, §104(2), Sept. 26, 1980, 94 Stat. 1233; amended Pub. L. 101–239, title VII, §7891(a)(1), Dec. 19, 1989, 103 Stat. 2445.)
Editorial Notes
Amendments
1989—Subsec. (b)(1). Pub. L. 101–239 substituted "Internal Revenue Code of 1986" for "Internal Revenue Code of 1954", which for purposes of codification was translated as "title 26" thus requiring no change in text.
Statutory Notes and Related Subsidiaries
Effective Date of 1989 Amendment
Amendment by Pub. L. 101–239 effective, except as otherwise provided, as if included in the provision of the Tax Reform Act of 1986, Pub. L. 99–514, to which such amendment relates, see section 7891(f) of Pub. L. 101–239, set out as a note under section 1002 of this title.
ERISA § 4213 (29 U.S.C. § 1393) — Actuarial assumptions · USC 2024 ed., current through 2025-01-06 · https://pensionresource.website/EAMain?content=EAMain.Law&id=usc29-1393&asof=1995-01-04 · printed Oct 16, 2026