Some credit unions are closed, serving only their members. However, the more and more popularitywin cooperatives of open type. Members of credit unions place in credit unions usually free fund balances, ie those that remain after expenses devoted to education of children, the acquisition of new properties, additional pension benefits, etc. 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. In the case of default the shareholder - individual will respond with its property and, in addition, is jointly and severally liable with the credit union's commitments. Credit unions base their activities on savings of shareholders, their shares and savings contributions, which make up the fund of mutual financial assistance - a source of cash loans to shareholders.