Typically new members of the credit union become citizens having suretyship or recommendations from their friends - members of the credit union. Among the U.S. credit unions, there are three groups that differ in terms of assets, shareholders, and business services. The relationship of shareholders with credit union are not client-based, they are co-operative, based on different principles and standards, in particular, on the principles of the law of obligations. As of the January 1, 2012 the national associations and confederations unite more than 196 million members participating in the 51,013 credit unions in 100 countries.