Fund of Mutual Financial Aid of the credit union can be extended by sponsorship contributions from businesses, organizations, including on a returnable basis. Typically, donor contributions to the credit unions are targeted and used in the same statutory requirements and restrictions as the Mutual Financial Aid fund as a whole. Most modern credit unions represent specialized consumer cooperatives of citizens associated by the principle of social community: place of work, place of residence, profession, or any other shared interest. 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. Credit union services are available only to its shareholders. 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. 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.