Specialization of credit unions to provide financial services to its shareholders requires a particularly strict regulation of membership and acceptable activities. 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. In the credit union compensation for use of the loan (interest) is a source of compensation for savings. In the UK, credit unions are a source of financing of people groups. This tool is not widely used. 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.