Author(s): Bushnell, James; Wolak, Frank A. | Abstract: Regulators of electricity markets around the world continue to struggle with the problem of incentivizing generators whose output, due to their location in the grid, has no viable substitutes. Such generators possess 'local' market power. Since these generators also compete in broader regional markets, the actions taken to exploit their local market power can also effect market outcomes over larger areas. In California, a contract structure known as the reliability must-run (RMR) contract was developed to address the problem of local market power. However, the contract form that was in place during 1998 created serious incentive problems. We find that, during the months of June through September 1998, RMR contracts had the effect of raising overall supply bid prices from most producers, thereby leading to higher energy prices in the California regional market.