The relations among the members of the first two types of groups are flexible, informal, and quite different from the holding company pattern of the prewar days. Coordination takes place at periodic gatherings of corporation presidents and chief executive officers. The purpose of these meetings is to exchange information and ideas rather than to command group operations in a formal way. The general trading firms associated with each group can also be used to coordinate group finance, production, and marketing policies, although none of these relationships is entirely exclusive. The practice of crossholding shares of group stock further cements these groups, and such holdings usually make up about 30 percent of the total group equity. Member corporations typically, although not exclusively, borrow from group banks.