Seyfarth Synopsis: Just before its summer recess, the Supreme Court agreed to review whether multiemployer pension funds can impose withdrawal liability based on actuarial assumptions adopted after the relevant plan year. The expected decision may have significant implications for employers’ ability to assess the impact of a contemplated withdrawal.

At the end of June, the Supreme Court granted certiorari in M & K Employee Solutions, LLC v. Trustees of the IAM National Pension Fund, No. 23-1209 (U.S. June 30, 2025 amended July 3, 2025) to consider an important question in calculating how much employers withdrawing from multiemployer pension funds are legally obligated to pay.

Withdrawing employers have to pay a portion of the fund’s unfunded vested benefits (i.e. the amount of vested benefits that a fund is legally obligated to pay but for which the fund does not have sufficient assets to meet). The withdrawal liability calculation is to be determined based on the fund’s financials as of the end of the plan year before the withdrawal. It can take many funds six months if not more after the end of a plan year to finalize their year-end financials and thus be able to issue a withdrawal liability assessment in the following plan year. In that interim, as the financials are being finalized, fund actuaries have on occasion changed actuarial assumptions, such as interest rates or mortality tables, retroactive to the prior plan year.Continue Reading Changing Last Year’s Assumptions This Year: Gotcha or Copacetic?