In many developing countries, where bank branches and A.T.M.’s are few or nonexistent in rural areas, cellphones may finally make financial services practical such places, fitting in the palm of one’s hand.

Mobile devices have the potential to take financial markets outside urban areas, allowing banks to provide services like loans and savings accounts in rural regions, according to a report by Vodafone and Nokia, published last week.

Microfinance institutions provide small loans and other services to the poor. But many businesses in the industry operate with outdated equipment like paper ledgers, complicating efforts to extend into areas where roads are inadequate and communication is expensive and unreliable.

When Vodafone began a pilot cellphone project in Kenya, Nick Hughes, the company’s head of international payments, said, “the idea was to reduce the cost of loan disbursal and recovery, but what we found was that customers were using it for person-to-person transfers.”