Pursuant to the Employee Retirement Income Security Act of 1974 (ERISA), as amended, an employer that stops participating in an underfunded Multiemployer Pension Plan (MPP), must pay the plan “withdrawal liability,” i.e., the employer’s share of the plan’s unfunded vested benefits (UVBs). See 29 U. S. C. §1391. Withdrawal liability is calculated based on the plan’s UVBs “as of ” the statutory measurement date—the last day of the plan year preceding the employer’s withdrawal. §§1391(b)(2)(E)(i), (c)(2)(C)(i), (3)(A), (4)(A). Determining the value of a plan’s UVBs depends upon both hard data (such as the number of beneficiaries and the value of the plan’s assets) and a variety of actuarial predictions about the future. One key actuarial assumption is the discount rate, which is the interest rate “used to discount future benefit payments to their present value.” 87 Fed. Reg. 62317.

Petitioners are four employers who withdrew from the IAM National Pension Fund (Fund)—an underfunded MPP—between April and December 2018. The Fund assessed each employer’s withdrawal liability “as of ” December 31, 2017 (the measurement date). In making this calculation, the Fund applied a discount rate of 6.50%, which it had adopted with its actuarial firm in January 2018. The Fund had previously used a discount rate of 7.50% to value its UVBs. Petitioners each initiated arbitrations challenging their assessments. In each case, the arbitrators determined that the assessments were erroneous because the Fund had applied actuarial assumptions adopted after the measurement date. The arbitrators instead required the Fund to use the actuarial assumptions that were “in effect” on the measurement date— i.e., the 7.50% discount rate. App. 293. The Fund sought review in Federal District Court. The courts disagreed with the arbitrators and held that actuaries could use assumptions adopted after the measurement date. The D.C. Circuit affirmed in a consolidated appeal. Its decision conflicted with a decision of the Second Circuit, and this Court granted certiorari to resolve when actuarial assumptions may be selected for purposes of calculating withdrawal liability.

Held: The provisions of ERISA governing the calculation of withdrawal liability—§§1391 and 1393—do not require the actuarial assumptions underlying that calculation to be selected on or before the measurement date. Pp. 6–11.

(a) Section 1391 requires withdrawal liability to be calculated based on the value of a plan’s UVBs “as of ” the measurement date. Petitioners contend that §1391’s “as of ” language establishes a deadline for the selection of actuarial assumptions. But §1391 sets no such deadline. The term “as of ” is understood “to assign an event to one time and the recognition of it to another.” W. Follett, Modern American Usage 41. Section 1391’s “as of ” language thus means that the hard data that feeds the UVB calculation must be fixed on the measurement date, but the calculation itself can be performed after that date. Actuarial assumptions are not observable facts about the plan; instead, they are predictive judgments used as tools to calculate UVBs. Accordingly, while §1391’s “as of ” requirement sets the reference point for factual inputs, it has no bearing on when actuaries must select their assumptions. Pp. 6–8.

(b) Section 1393, which governs the use of actuarial assumptions for assessing withdrawal liability, states that the assumptions must be “reasonable,” “tak[e] into account the experience of the plan and reasonable expectations,” and “offer the actuary’s best estimate of anticipated experience under the plan.” §1393(a)(1). Section 1393 provides no deadline by which actuaries must select their assumptions, and the Court does not generally read limitations into statutes that do not appear in their text. Romag Fasteners, Inc. v. Fossil Group, Inc., 590 U. S. 212, 215. Indeed, because Congress included a deadline for the selection of actuarial assumptions in a different section of the statute, but imposed no similar limit in §1393, the Court presumes that the omission in §1393 is intentional. See Russello v. United States, 464 U. S. 16, 23. Moreover, §1393’s instruction that actuarial assumptions reflect the actuary’s “best estimate,” §1393(a)(1), supports the conclusion that actuaries can select their assumptions after the measurement date. Requiring actuaries to use assumptions selected before the measurement date could prevent them from relying on the most up-to-date data when selecting their assumptions, resulting in assumptions

that do not reflect their “best estimate.” Pp. 8–10.

(c) Petitioners’ remaining arguments do not overcome the absence of a textual deadline for adopting actuarial assumptions. First, petitioners point to a different provision of ERISA that prohibits plans from applying any new “plan rule or amendment” to an employer’s withdrawal liability if the rule or amendment is adopted after the employer withdraws. §1394(a). But the retroactivity limits in §1394 concededly do not apply to actuarial assumptions. Congress chose not to enact a similar antiretroactivity rule in §1393, and inferring one would override Congress’s choice. Petitioners fall back on a policy argument, contending that allowing plans to adopt actuarial assumptions after the measurement date will invite manipulation, enabling plans and their actuaries to retroactively select assumptions in order to increase withdrawing employers’ liability. But petitioners’ proposed rule does not address these concerns, and in any event, “policy concerns cannot trump the best interpretation of the statutory text.” Patel v. Garland, 596 U. S. 328, 346. Congress chose which limits to impose on the selection of actuarial assumptions, and it is not the role of the Court to supplant Congress’s choices. Pp. 10–11.

92 F. 4th 316, affirmed.

JACKSON, J., delivered the opinion for a unanimous Court.

https://www.supremecourt.gov/opinions/25pdf/23-1209_i3kn.pdf