Some credit unions are closed, serving only their members. However, the more and more popularitywin cooperatives of open type. When organizing the credit union it is important that people know each other and know the extent to which each of them is trustworthy. Credit union services are available only to its shareholders. 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. Today, the World Council of Credit Unions is represented as members four regional confederations and twelve national associations. 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.