In a world of increasing capital requirements and intensifying regulation, banks are struggling to achieve double-digit returns on equity. Credit cards are one bright spot. In 2014, for example, Barclays earned a 5.1% ROE at the group level. Its credit card business generated a 16% ROE.
With those relative returns, it's understandable that banks want to grow their credit card businesses and are investing heavily in product development and marketing. It's likely that they will be able to continue generating big returns in the short term, thanks to cyclically low credit losses and funding costs in the aftermath of the financial crisis. Returns will probably normalize as credit losses and reserves increase through the natural credit cycle.