Credit union is created by a group of members who pursue a common interest. Agreeing to make regular contributions, they create a fund from which can borrow money for investments and replenishment of working capital at favorable interest rates. 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. 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 right to use the services of the credit union have only its members. 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. Worldwide credit union movement is represented by regional confederations and national organizations within the World Council of Credit Unions. Corporate alliances are intermediaries between credit unions and financial markets.