Our purpose is to provide an explanation for the existence of such contracts because this contract is uniformly used in the United States, Canada and Japan and has been for quite some time. At the same tie, an institution that represents the buyer's interests has not emerged. As with any long-lived, widely used institution, there is reason to believe that it serves a useful purpose which cannot be served by an alternate institution in which the buyer is represented by his own agent.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100732/1/ECON019.pd