William Hogan Harvard University Wholesale electricity markets in the United States stand on the principles of open access and nondiscrimination. These principles substantially constrain the design of electricity markets to follow the model of bid-based, security-constrained, economic dispatch with locational prices. This model governs short-term operations, provides the foundation for financial transmission rights, and supports forward trading. The basics of this design are now found in all the organized electricity markets. There is a strong, but not complete, connection between the optimization formulation and the equilibrium description of the resulting market outcomes. William Hogan Harvard University Wholesale electricity markets in the United States stand on the principles of open access and nondiscrimination. These principles substantially constrain the design of electricity markets to follow the model of bid-based, security-constrained, economic dispatch with locational prices. This model governs short-term operations, provides the foundation for financial transmission rights, and supports forward trading. The basics of this design are now found in all the organized electricity markets. There is a strong, but not complete, connection between the optimization formulation and the equilibrium description of the resulting market outcomes.