The number of people banking through a mobile device could hit half a billion worldwide by 2013, according to ABI Research. "Mobile financial services have the potential to be bigger than mobile TV and premium mobile content in terms of numbers of subscribers," Mark Beccue, senior analyst of consumer mobility, tells Marketing Daily. "Everybody's trying to do it, and they're all scrambling."

The drive for more and better mobile financial services applications is being fed by consumers who are becoming more accustomed to banking online. "The lowest-hanging fruit are the online customers," Beccue says. "That's one of the only barriers to mobile banking; if you don't trust online, you won't trust mobile."

But just as customers are using online banking for uses beyond simply checking their accounts, they will begin to use their mobile devices for those purposes as well. "The growing parts will be more sophisticated applications like bill payment," Beccue says. But banks will have to work on making the mobile experiences as simple and user-friendly as the online services.

Increasing numbers of customers--particularly younger ones--are learning to trust the online space for their banking, and mobile will quickly follow. "Generation Y expects mobile to be part of what they're doing, and banking is no different," Beccue says.

In the U.S., the mobile banking leader is Bank of America, Beccue says. The bank launched its mobile service in May 2007, and by the end of 2008 it had 1.5 million subscribers. "It's a growing segment, and it's being led by Bank of America," Beccue says.