In 1908. the spread of credit unions has reached the United States. In 1935 President Roosevelt signed the state Charter on credit unions, which became a law. Activity of the credit union consists of organizing mutual financial assistance by meeting the needs of its members in the services of saving and obtaining loans. 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. 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.