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. Corporate credit unions are united on a cooperative basis in the Central Credit Union (US Central Credit Union). National Credit Union Administration (NCUA) - an independent federal agency, based in Washington (State of Columbia), established by the U.S. Congress to oversee the federal credit union system. Credit unions perform the function of social protection in a vital for people sphere of financial services. They care about improving the financial literacy of the population, are working on the formation of their members and their employees. Historically, credit unions have grown from the experience of credit cooperatives, but they took the experience of organizations of mutual aid of citizens by moving methods of social self-protection from labor and toward consumption. 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. Worldwide credit union movement is represented by regional confederations and national organizations within the World Council of Credit Unions.