Credit card loans are increasing as a percentage of credit unions' total assets at the same time they are declining as a percentage of total assets at commercial banks, according to financial consulting firm SNL Financial.

“At the end of 2010, aggregate credit card loans and other revolving credit plans stood at $36.37 billion at U.S. credit unions, accounting for 6.35% of their total loans,” SNL analysts reported on Thursday. “By Sept. 30, 2012, that number had grown to $38.25 billion, or 6.39% of the total loan portfolio.”

By contrast, credit card loans at commercial banks moved from 10.78% of their loan portfolios at the end of 2010 to 9.70% at the end of the third quarter of 2012.

Credit unions also beat commercial banks with the lowest rates, the firm reported.

The 86,000-member, $744 million Educational Systems FCU in Maryland led the country with a 3.25% average rate, while the $244 million Energy One FCU in Tulsa, Okla., came in second with an average platinum rate of 4.25%, followed by the $422 million Sandia Area FCU in Albuquerque, N.M., at 4.99%.