Energy Markets: Estimates of the Effects of Mergers and Market Concentration on Wholesale Gasoline Prices

In 2008, GAO reported that 1,088 oil industry mergers occurred between 2000 and 2007. Given the potential for price effects, GAO recommended that the Federal Trade Commission (FTC), the agency with the authority to maintain petroleum industry competition, undertake more regular retrospective reviews of past petroleum industry mergers, and FTC said it would consider this recommendation. GAO was asked to conduct such a review of its own to determine how mergers and market concentration--a measure of the number and market shares of firms in a market--affected wholesale gasoline prices since 2000. GAO examined the effects of mergers and market concentration using an economic model that ruled out the effects of many other factors. GAO consulted with a number of experts and used both public and private data in developing the model. GAO tested the model under a variety of assumptions to address some of its limitations. GAO also interviewed petroleum market participants.