Among the U.S. credit unions, there are three groups that differ in terms of assets, shareholders, and business services. Share contributions are transferred to the credit union on the basis of membership for the whole stay of a shareholder as member of the credit union and are the basis of membership. A potential new member of a credit union must submit a recommendation of shareholders in which the referee becomes a warrant of a future member of the credit union. Until the 70's there was a proliferation of the U.S. credit unions due to the increase of their number and the number of shareholders, although it must be acknowledged that there was also and a qualitative growth. The relationship of shareholders with credit union are not client-based, they are co-operative, based on different principles and standards, in particular, on the principles of the law of obligations. In the credit union compensation for use of the loan (interest) is a source of compensation for savings. The main activities of credit unions, aimed at the organization of mutual aid and social support of citizens is not intended to profit. Unlike banks, in order to use the services of a credit union, you have to become its member, having written an application and having paid thus shares and membership fee.