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

Docket Number: 23-1209
Citation: 608/1
Term: October Term 2025
Argued: January 20, 2026
Decided: May 21, 2026
Lower Court: United States Court of Appeals for the District of Columbia Circuit
Author: Associate Justice Ketanji Brown Jackson
Concurring: Ketanji Brown Jackson

AI-Generated Summary

Case Information:

Case Name: M & K Employee Solutions, LLC, et al. v. Trustees of the IAM National Pension Fund
Docket Number: 23–1209
Dates: Argued January 20, 2026; Decided May 21, 2026
Lower Court: United States Court of Appeals for the District of Columbia Circuit

Facts of the Case:

Petitioners, four employers, withdrew from the IAM National Pension Fund (an underfunded multiemployer pension plan) between April and December 2018. The Fund calculated each employer’s withdrawal liability “as of” December 31, 2017, using a 6.50% discount rate adopted in January 2018 (previously the Fund had used 7.50%). This change substantially increased the assessed liability. Petitioners challenged the assessments in arbitration, arguing that the Fund should have used only actuarial assumptions “in effect” on the measurement date. Arbitrators sided with petitioners. The Fund sought judicial review. District courts ruled that actuaries could use assumptions adopted after the measurement date. The D.C. Circuit affirmed in a consolidated appeal. The decision conflicted with a Second Circuit ruling, prompting the Supreme Court to grant certiorari.

Legal Issues Presented:

The Court addressed whether ERISA provisions governing withdrawal liability calculation (§§1391 and 1393) require actuarial assumptions to be selected on or before the statutory measurement date (the last day of the plan year preceding withdrawal). The case involves statutory interpretation of ERISA. Petitioners contended that §1391’s “as of” language imposes a deadline for selecting assumptions. The Fund argued that the statute imposes no such timing restriction.

The Court's Decision (Main Opinion):

Author & Type: Justice Jackson delivered the opinion for a unanimous Court.
Holding: ERISA §§1391 and 1393 do not require actuarial assumptions underlying withdrawal liability calculations to be selected on or before the measurement date.
Legal Reasoning: Section 1391’s “as of” language fixes hard factual data about the plan on the measurement date but does not govern the timing of predictive actuarial tools such as assumptions. Section 1393 requires assumptions to be reasonable and to reflect the actuary’s “best estimate,” without imposing any selection deadline. The Court declined to infer a deadline absent textual support and noted that Congress had included deadlines elsewhere in the statute. Requiring pre-measurement-date assumptions could prevent use of the most current relevant data, undermining the “best estimate” requirement.
Disposition: The judgment of the D.C. Circuit was affirmed.

Concurring Opinion(s): None (unanimous opinion).

Dissenting Opinion(s): None (unanimous opinion).

Potential Significance:

The ruling clarifies that actuaries may adopt assumptions after the measurement date when calculating withdrawal liability, provided the assumptions are reasonable and constitute the actuary’s best estimate of anticipated plan experience. It emphasizes that §1391 addresses factual inputs while §1393 governs the tools used for valuation.

This summary was generated by AI and may contain inaccuracies. Refer to the official source document for the authoritative text.

Key terms: Pension Plan Withdrawals, Actuarial Assumptions, Liability Calculations