Retail banks in developing economies face a tough choice. They can remain in their current niches of serving their handful of well-to-do customers or they can take a page out of the mobile industry’s book, update their retailing knowledge, and modify their infrastructure to bring electronic financial services to the millions at the bottom of the income pyramid. To do that, they have to leverage mobile communications. This is no easy task. But if they do not, they run the significant risk of concentrating banking power in the one or two banks per country or region that had the foresight to work as deposit account and cash managers with emerging mobile money services (MMS) and their coordinating mobile network operators (MNOs) operating in scores of developing countries.