This year, 115.6 million mobile phone users in the US will bank on mobile at least once per month, according to eMarketer estimates.
Growth, however, will slow through the end of the forecasting period—from 6.6% by the end of 2018 to just 3% in 2022.
"Growth is slowing because mobile banking has reached near saturation among younger consumers," said eMarketer forecasting analyst Cindy Liu. "While penetration is still very low with older individuals, they are just not interested in mobile banking for numerous reasons."
Privacy and security are among the key factors driving decelerated mobile banking growth.
Mass data breaches from companies like Equifax, JPMorgan Chase, and most recently Marriott, have made consumers—especially older consumers, even more hesitant to trust anyone with their financial information.
Limited functionality with mobile banking is another factor.
An April 2018 survey from Morning Consult found that for the most part, internet users in the US will check an account or a balance or pay their bills online.
"Beyond these activities, there really aren't more banking features that consumers can access via mobile," Liu said.
Like with peer-to-peer payments (P2P), millennials are banking on their mobile phones at a much higher rate than older generations. We estimate that there will be 50.3 million millennial mobile phone banking users in the US by the end of 2018.
In contrast, we expect 31.5 million Gen Xers to bank on mobile, and 17.6 million boomers to do so as well.
"Mobile banking may seem too complicated for older consumers, who are just more comfortable using a desktop or conducting their financial transactions in-person," Liu said.
Investment app startups like Robinhood and Betterment have gained traction in the news recently for apps largely targeted at people just getting their start in investing, and at the same time, established financial institutions are also making big bets on mobile apps.
In August 2018, JP Morgan Chase launched a digital investing service with lower fees than it previously offered and 100 free trades in the first year to anyone who downloaded its mobile banking app or used its websites. Bank of America said it tripled its mobile banking budget from 2015 to 2016 and it remained at that level throughout 2017. And last week, T-Mobile announced that it was getting back into mobile banking with the launch of its T-Mobile Money app.