Changing the Numbers After the Fact

Xylee Alvarez

January 2026

The Court considers whether pension plans may change actuarial assumptions after the clock has run. 

At first glance, M & K Employee Solutions, LLC v. Trustees of the IAM Pension Fund, sounds quite dry and technical. However, after following the case and hearing oral arguments, I learned that the Court was grappling with whether statutory timing requirements actually mean what they say, or whether they can be bent in favor of administrative convenience. 

Under ERISA, when an employer withdraws from an underfunded multiemployer pension plan, it must pay “withdrawal liability,” calculated as of the end of the plan year preceding the withdrawal. The statute is clear about when the calculation is supposed to occur. What it does not spell out is whether the actuarial assumptions used in that calculation must be the ones in place at the end of the year,  or whether plans may later revise those assumptions and apply them retroactively.  The difference can mean millions of dollars. 

From the bench, several Justices appeared less focused on the statutory text than on the consequences of enforcing it strictly. Questions from Justices Alito and Kavanaugh suggested unease with a rule that would “freeze” actuarial assumptions at a single point in time, even if later data suggests that those assumptions were optimistic or outdated. 

That concern reveals an important instinct of the modern Court; flexibility often matters more than finality, especially when institutional actors like pension plans are involved. 

Chief Justice Roberts’ questions reinforced this concern. He focused a lot on whether Congress truly intended to lock plans into assumptions that could quickly become inaccurate, or whether the statute allows room for professional judgment after the plan year closes. His framing hinted at a willingness to read ambiguity into language that appears quite precise. 

On the other side, the argument for employers is straightforward. If plans are allowed to adopt new actuarial assumptions after the year ends and then apply them retroactively, employers lose any ability to predict or rely on their financial obligations. Timing becomes meaningless, and withdrawal liability becomes a moving target. 

Justice Kagan pressed on this point, emphasizing that ERISA is filled with deadlines for a reason. Her questions suggested discomfort with an interpretation that turns a statutory snapshot into a very open ended process. Justice Jackson similarly questioned whether allowing retroactive assumption changes undermines basic principles of notice and fairness. 

Still, these concerns felt overshadowed by the fact that a lot of money is at stake here. 

Based on the oral argument, the Court appears likely to rule in favor of the pension plan, holding that ERISA permits the use of actuarial assumptions adopted after the end of the plan year. The conservative majority seems inclined to prioritize that flexibility and professional discretion over strict textual timing. The ruling will likely be very technical because when “as of the end of the year” no longer means as of the end of the year, certainty disappears, while power fills the gap.