Sitting in front of a room full of bankers at the Mobile Banking and Commerce Summit in San Francisco, some of the biggest players in the burgeoning mobile wallet space wasted no time Tuesday tackling that question. The query itself suggested that banks still don't know enough about the power of mobile wallets and the potential benefits of partnering with their developers.

"Banks, telecoms and payment companies are part of the ecosystem as [participants]; at MasterCard, we want to work with ISIS, Google and banks," said MasterCard Worldwide (MA) Group Head and Senior Vice President James Anderson, who acknowledged the difficulty of a fully open mobile wallet model among stakeholders who will retain some propriety. "A single wallet is unlikely, at least in a free market."