This paper argues that Jewish merchants have historically dominated the diamond industry because of their ability to reliably implement diamond credit sales. Success in the industry requires enforcing executory agreements that are beyond the reach of public courts, and Jewish diamond merchants enforce such contracts with a reputation mechanism supported by a distinctive set of industry, family, and community institutions. An industry arbitration system publicizes promises that are not kept. Intergenerational legacies induce merchants to deal honestly through their very last transaction, so that their children may inherit valuable livelihoods. And ultra-Orthodox Jews, for whom participation in their communities is paramount, provide important value-added services to the industry without posing the threat of theft and flight
