Opinion Summary: M & K v. IAM Pension Trustees | Pension Plan Predicament Put to Rest

I'll create show notes and five alternative episode title options for this opinion episode.Now I'll create the show notes and title options for the M & K Employee Solutions opinion episode.

PART 1: SHOW NOTES

M & K Employee Solutions, LLC v. Trustees of IAM National Pension Fund | Case No. 23-1209 | Decided May 21, 2026 | Docket Link: https://www.supremecourt.gov/docket/docketfiles/html/public/23-1209.html

Overview: ERISA withdrawal liability dispute resolves when pension plan actuaries must select calculation assumptions, affecting billions in retirement obligations across multiemployer pension plans serving unionized workers nationwide.

Question Presented: Whether ERISA requires actuarial assumptions underlying withdrawal liability calculations get selected on or before the statutory measurement date.

Posture: D.C. Circuit affirmed district courts allowing post-measurement-date assumption selection, conflicting with Second Circuit precedent.

Main Arguments:

• Employers (Petitioners): (1) Statute's "as of" language freezes all calculation inputs including assumptions on measurement date; (2) Actuarial assumptions constitute factual inputs requiring temporal fixation; (3) Broad anti-retroactivity principle prevents post-measurement assumption adoption.
• Pension Fund (Respondent): (1) "As of" language sets reference point for hard data only while tools get selected later; (2) Actuarial assumptions constitute analytical methods not observable facts; (3) "Best estimate" requirement supports using most current available data when selecting assumptions.

Holding: The ERISA provisions governing the calculation of withdrawal liability from an underfunded Multiemployer Pension Plan do not require that actuarial assumptions underlying the calculation be selected on or before the statutory measurement date.

Voting Breakdown: 9-0. Justice Jackson wrote the majority opinion joined by Roberts, Thomas, Alito, Sotomayor, Kagan, Gorsuch, Kavanaugh, and Barrett. Affirmed D.C. Circuit.

Opinion: Here

Majority Reasoning: (1) Section 1391's "as of" language assigns hard data to measurement date but permits calculation performance afterward using tools including assumptions; (2) Section 1393 imposes no deadline for assumption selection and Congress's omission from parallel provisions signals intentional choice; (3) "Best estimate" requirement necessitates access to most current data potentially unavailable before measurement date.

Implications: Pension plans gain flexibility to select actuarial assumptions after measurement dates using current market data and professional judgment. Employers lose timing-based challenges but retain substantive reasonableness challenges through arbitration. Actuaries avoid artificial deadlines while maintaining accountability through reasonableness requirements. Court leaves open whether assumptions must reflect only information available as of measurement date.

The Fine Print:

• 29 U.S.C. § 1391(b)(2)(E)(i): Withdrawal liability calculated based on plan's unfunded vested benefits "as of" the last day of plan year preceding employer's withdrawal
• 29 U.S.C. § 1393(a)(1): Actuaries must use "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"

Primary Cases:

• Russello v. United States (1983): Where Congress includes particular language in one statutory section but omits it in another section of same Act, courts presume Congress acts intentionally and purposely in disparate inclusion or exclusion
• Romag Fasteners, Inc. v. Fossil Group, Inc. (2020): Courts generally decline reading limitations into statutes that do not appear in their text

Oral Advocates:

• For Petitioner (M&K Employee Solutions): Michael E. Kenneally, Jr., Washington, D.C.
• For Respondent (IAM National Pension Fund): John E. Roberts, Providence, Rhode Island.
• For United States as (Amicus Curiae Supporting Respondent): Kevin J. Barber, Assistant to the Solicitor General, Department of Justice.