Has the D.C. Circuit improperly extended Chevron deference to PBGC's construction of ambiguous statutory provisions in informal, non-binding adjudications undertaken not in the agency's congressionally assigned role as insurer (or in any other regulatory capacity) but instead as a plan trustee and fiduciary?

QUESTION PRESENTED Title IV of the Employee Retirement Income Security Act (“ERISA”) charges the Pension Benefit Guaranty Corporation (“PBGC”) with administering a federal insurance program covering certain pension plans. PBGC collects premiums from plan sponsors; deposits the premiums into a revolving fund; and, if a plan terminates with insufficient assets, draws from the fund to pay “guaranteed” benefits. Separate from its statutory obligations as a guarantor, PBGC may volunteer for a second role: trustee of a terminated plan. As trustee, PBGC becomes a fiduciary and assumes duties from the private “plan administrator.” One duty is to distribute, pursuant to 29 U.S.C. §1344(a), the terminated plan’s remaining assets among various groups of beneficiaries. Beneficiaries who disagree with PBGC’s asset allocations can sue in federal court after review before the agency’s Appeals Board. The Board’s decision, which is informal and non-binding on other parties, often turns on the construction of ambiguous language in §1344(a). When there is ambiguity (as here), PBGC insists that the Board’s construction deserves deference under Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984). The question presented—which, for reasons discussed below, can arise only in the D.C. Circuit—is: Has the D.C. Circuit improperly extended Chevron deference to PBGC’s construction of ambiguous statutory provisions in informal, non-binding adjudications undertaken not in the agency’s congressionally assigned role as insurer (or in any other regulatory capacity) but instead as a plan trustee and fiduciary?