First, the contractual parties may engage in a great deal of haggling over the terms of the revised contract. Argument about division of surplus serves no overall productive purpose and, to the extent that haggling is time-consuming and wastes resources, such haggling is inefficient. Second, there may be costly legal disputes because an incomplete contract will be ambiguous, and the contractual parties will look to the courts to resolve the ambiguity. Third, not only may the process of ex post bargaining be costly, but also to the extent that the contractual parties have asymmetric information, the contractual parties may fail to reach an efficient agreement.