A common theme in restructured electricity systems around the world is the unbundling of generation, transmission, and distribution and the creation of independent transmission entities that link competitive generation to regulated distribution. The transmission sector, which enables wholesale competition in the electricity industry, is viewed as the centerpiece of restructured systems. Consequently, the requirement that all market participants have nondiscriminatory access to the transmission system is the key requirement for facilitating competitive markets. The central question that this paper addresses is what transmission system governance structure and business model can most effectively support the objective of promoting competition through nondiscriminatory access to the grid. Transmission system business models define the relationship among the three basic business functions associated with the provision of transmission service: system operations, market operation, and grid ownership.