At the organization of the credit union it is important that people know each other and know the extent to which each of them is trustworthy. To reduce the risk of default on loans members of the credit union shall the joint guarantee. 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. The right to use the services of the credit union have only its members.