Membership in the credit union is voluntary and is open to all citizens bound by with joint work or residence, who wished to create a credit union to use its services and are willing to take on relevant commitments and responsibilities. Today in the UK there are about 700 credit unions with assets exceeding 200 million pounds. 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. 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. Taking a decision to join a credit union, citizens create an organization through which they participate in the shared savings by mutual crediting and joint (collective) use of personal savings. The relationship between credit unions and shareholders arise from the membership and are not customer relationship. To increase the number of credit unions in 1979 was adopted the corresponding law that serves as the legal basis of their activity. Worldwide credit union movement is represented by regional confederations and national organizations within the World Council of Credit Unions.