Corporate credit unions are united on a cooperative basis in the Central Credit Union (US Central Credit Union). Is necessary that all shareholders of the credit union were members of a single community, would know each other well enough to enjoy mutual trust. International cooperation has been particularly felt since the days when Alphonse Desjardins began the activity on development of credit union movement in North America. The value of credit unions is not limited to the role of the economic agent - they are an important element of the social structure and a factor of social stability and progress. Credit unions historically formed as a special form of social support, initially taken upon themselves the social mission of protecting the interests of citizens in the field of financial services. 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.