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Project Curia
Supreme Court decisions
No. 23-1209May 21, 2026Labor and EmploymentAffirmed

The question

Whether the ERISA provisions governing withdrawal liability require the actuarial assumptions used in that calculation to be selected on or before the statutory measurement date.

M & K Employee Solutions, Inc. v. Trustees of IAM Nat. Pension

What the Court decided

The Court held that ERISA does not require the actuarial assumptions used to calculate withdrawal liability to be selected on or before the measurement date. Sections 1391 and 1393 set no such deadline. The "as of" language in Section 1391 fixes the hard data inputs to the measurement date but does not govern when actuaries must choose their predictive assumptions, and Section 1393 imposes no timing limit on assumption selection.

How the justices split

Unanimous
In favor 9
Jackson
Roberts
Thomas
Alito
Sotomayor
Kagan
Gorsuch
Kavanaugh
Barrett

The Court's opinion

Jackson, joined by Roberts, Thomas, Alito, Sotomayor, Kagan, Gorsuch, Kavanaugh, Barrett

The opinion held that neither Section 1391 nor Section 1393 requires actuarial assumptions to be selected by the measurement date. The 'as of' language in Section 1391 fixes the hard data feeding the calculation to the measurement date but does not govern the timing of actuarial assumptions, which are predictive judgments rather than observable facts. Section 1393 sets no deadline for selecting assumptions, and because Congress imposed a deadline elsewhere in the statute but not in Section 1393, the omission is presumed intentional. Section 1393's instruction that assumptions reflect the actuary's best estimate supports allowing selection after the measurement date so actuaries can rely on the most up to date data.

How we know · 5 sourced claims
  • The Court held that ERISA Sections 1391 and 1393 do not require actuarial assumptions to be selected on or before the measurement date.

    Source: syllabus, Held

  • Section 1391's 'as of' language fixes the hard data feeding the UVB calculation to the measurement date, but the calculation itself can be performed after that date.

    Source: syllabus, Held

  • Because Congress included a deadline for selecting actuarial assumptions in a different section of the statute but imposed no similar limit in Section 1393, the Court presumed the omission was intentional.

    Source: syllabus, Held

  • The petitioners are four employers who withdrew from the underfunded IAM National Pension Fund between April and December 2018, and the Fund assessed their withdrawal liability using a 6.50% discount rate adopted in January 2018.

    Source: syllabus, Held

  • Justice Jackson delivered the opinion for a unanimous Court.

    Source: syllabus, lineup

Read the opinion on supremecourt.gov