Intermediaries, such as accountants, lawyers, and bankers, are gatekeepers, which are parties whose cooperation is necessary for corporations to function and who, by withholding cooperation, are able to prevent significant corporate misconduct. The recent scandals at Enron and other corporations were due, in part, to failures by gatekeeper institutions. However, intermediaries exist primarily to provide for-fee services and not specifically to detect and deter misconduct. Insofar as these institutions are gatekeepers or guardians, they serve reluctantly. Hence the question: What is the responsibility of intermediaries to act as gatekeepers? This article argues that the appropriate moral, as well as legal, principle for justifying responsibility in a gatekeeper role is cost effectiveness. This conclusion is reached by means of a hypothetical exercise called the investors’ bargain in which investors—who bear the costs and receive the benefits of intermediaries’ gatekeeper role—are asked to choose the best means of protecting their interests.