Some credit unions are closed, serving only their members. However, the more and more popularitywin cooperatives of open type. The number of shareholders of a credit union is limited and formalized by a list. Limit of the number is defined by the assembly and such assembly establishes the charter. Cooperation between credit unions, how they would not have been named, took place always, from the moment when the movement moved outside one credit union. 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. Credit unions are competitors of savings institutions, adding interest on deposits of members. This applies to the shares, as well as to additional funds transferred to the account in the credit union. The specifics of credit unions and, in some sense, their uniqueness lies in the fact that they work not for profit and do not appropriate profit.