Corporate credit unions are united on a cooperative basis in the Central Credit Union (US Central Credit Union). Like the credit cooperatives, credit unions form associations of a higher level, which are called corporate credit unions. Among the U.S. credit unions, there are three groups that differ in terms of assets, shareholders, and business services. Cooperation between credit unions, how they would not have been named, took place always, from the moment when the movement moved outside one credit union. Over 30% of the assets of credit unions are investments in government securities, certificates of deposit of banks and savings loan associations, as well as in the parent credit unions, and other risk-free investments. Unlike banks, in order to use the services of a credit union, you have to become its member, having written an application and having paid thus shares and membership fee.