Robert Clarke (defendant), the federal Comptroller of the Currency, approved a California national bank's application to establish a discount-brokerage affiliate. The affiliate would operate out of the bank's branch offices and at non-branch locations, both in California and in other states. The Securities Industry Association (SIA) (plaintiff) represented security dealers that competed with banks to provide discount-brokerage services. The SIA sued Clarke, contending that Clarke's approval of the bank's application violated two provisions of the McFadden Act, codified at 12 U.S.C. §§ 36 and 81. Section 81 stated that a national bank's general business could be conducted only at the bank's headquarters and branch offices. Section 36 required that branch offices both be in the bank’s home state and comply with the bank’s home state's branching laws. Clarke argued that the SIA was outside the zone of interests protected by the McFadden Act, and, therefore, the SIA lacked standing to sue under the McFadden Act. A federal district court rejected that argument and ruled in the SIA's favor on substantive grounds. The court of appeals affirmed, and the United States Supreme Court granted certiorari to hear the case.