J.P. Morgan's Jamie Dimon still gets excited when he talks about the Chase banking app. He should -- Chase had 25 million active monthly users on its mobile banking app as of June of 2016. Overall banking app usage is still growing as mobile apps have become table stakes for retail banks. The data shows that financial services customers want to be able to access their banks, investment accounts, and cash whenever and wherever they want. Big banks have migrated a lot of users to mobile [caption id="attachment_12891" align="aligncenter" width="575"] Source: The Motley Fool[/caption] JPMorgan Chase is the frontrunner with 25 million actively monthly users on the Chase app. According to data from The Motley Fool, Bank America (with 20 million monthly users) and Wells Fargo (with 18 million) aren't far behind. Interestingly, the size of these banks' mobile userbases tracks the relative size of these banks when you look at their assets. Banks are working to migrate customers to digital channels as costs to service them on mobile, for example, are up to 90 percent lower than via a branch. More banking customers are using mobile [caption id="attachment_12893" align="aligncenter" width="600"] Source: App Annie[/caption] Growth continues in mobile banking, even if it may be leveling off. According to mobile research firm App Annie, 2016 ended with record levels of engagement on mobile apps. The top 10 mobile banking apps actually saw the highest level of monthly active users they've ever experienced, increasing 30 percent from the same period in 2014. Young users driving growth of mobile banking apps [caption id="attachment_12895" align="aligncenter" width="575"] Source: App Annie[/caption] Users under the age of 45 years old are driving the growth in mobile banking. Over the past two years, the average number of U.S. mobile banking users in this age bracket has increased about 15 percent. MAU for banking customers over the age of 45 are headed in the opposite direction. This demographic doesn't feel as comfortable banking on a mobile device and frequently turns to telephone banking or in-branch visits to get service. Sometimes, it's not just the medium that holds users back from embracing the technology. Buggy apps create bad experiences that customers aren't likely to want to repeat. "The critical reviews (i.e., one- or two-star reviews) of the top 10 retail banking apps by MAU in Q4 2016 reveal that the most frequent feature complaint is the reliability of the app, including updates, crashes and errors," said App Annie's Lexi Sydow. Growth in mobile banking is slowing [caption id="attachment_12899" align="aligncenter" width="629"] Source: Bain & Co.[/caption] While the largest U.S. banks are enjoying record numbers of monthly users to their banking apps, that growth appears to be slowing down. According to recent research from Bain & Co., bank customers who haven't quite made the switch to mobile will require extra guidance to move their banking to an app, especially if they're in an older age group. "Banks should continue to streamline the experience of using both mobile or online channels, so that consumers turn to those channels before the branch or contact center," wrote the authors of the Bain study.