Credit unions also differ from the traditional consumer cooperatives. Typically new members of the credit union become citizens having suretyship or recommendations from their friends - members of the credit union. 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. 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. 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. To increase the number of credit unions in 1979 was adopted the corresponding law that serves as the legal basis of their activity.