JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.Studies of the largest contemporary fortunes in Great Britain, the United States, and Australia each find that over two-thirds of the fortunes originated in competitive industries. A finding that market power is responsible for only one-third of the wealth of the wealthiest individuals is consistent with earlier research. Great fortunes can arise from competitive industries because of risk and uncertainty, infra-marginal (Ricardian) rents, and disequilibrium. * The authors would like to thank Lawrence J. White and two anonymous referees for helpful comments. 1 For a summary of research concerning the effects of market power on the wealth distribution, 277 This content downloaded from 128.235.251.160 on Fri, 12 Dec 2014 03:56:08 AM All use subject to JSTOR Terms and Conditions 7The populations of the UK, US, and Australia, respectively, were 57 million, 250 million, and 17 million (Source: Statistical Abstract of the United States, 1992