Drawn by their corporate responsibility agendas and the promise of profitability, commercial banks have been entering the microfinance market, with Credit Agricole and JPMorgan among recent entrants. But when it comes to serving the 4bn people living on less than $2 a day, traditional microfinance models are not the only means of expanding access to financial services.

In Ghana, for example, Barclaysoffers deposit accounts to traditional "Susu" collectors, who form part of an ancient system of saving. Some institutions are starting to expand into insurance and savings, while some banks are delivering services through mobile phones.

The microfinance industry has been prominent in offering banking services to the poor. Microfinance hit the headlines in 2006, when the Nobel peace prize was awarded to Muhammad Yunus, a Bangladeshi banker who pioneered the idea of providing small loans to villagers.

Microfinance may even become an asset class for investors. In May, the International Finance Corporation, part of the World Bank Group, announced an investment of $45m in credit-linked notes to be issued by a vehicle set up by Standard Chartered to facilitate microfinance lending in sub-Saharan Africa and south Asia.

Meanwhile, microfinance has become one of the main instruments through which the poor access financial services. In Bangladesh, ASA, the microfinance group, operates a decentralised model in which simplified accounting and record keeping removes the need to have separate accountants and cashiers in branches.

In India, ICICI Bank offers a range of products to rural and low-income customers, including savings and life insurance services. Its micro-savings product allows clients to maintain a zero opening balance, while other products include insurance to help protect clients from illness and crop failure.

Increasingly, organisations are recognising that these savings and insurance options are as important for poor customers as micro-loans.

Opportunity International Bank of Malawi (OIBM), for example, has moved away from traditional microfinance to focus on savings accounts. "The poorest people are not often able to run a small business, which is what micro-credit organisations focus on," says Deborah Foy, international programmes director at Opportunity International UK. "Usually poor people do save, but they tend to save in a tin pot."

OIBM, which has also developed a weather-indexed insurance product, based its model on biometric technology. No formal identification documents are needed to open a savings account and, for those who are illiterate, no forms need to be filled out.

Moreover, the system helps women in Malawi, where a wife whose husband dies has to surrender her possessions to his family. "Because these savings accounts are biometric, only the widow can access the assets," says Ms Foy. "That's really empowering for these women."

Some institutions are serving poor markets through banking models. In Brazil, Banco Bradesco's Banco Postal service operates in post office branches and now has more than 6m clients. "The numbers demonstrate the success of the initiative," says Lincoln Cesario Fernandes, social-environmental responsibility manager at Banco Bradesco. "Five thousand new current accounts in the Banco Postal are opened daily."

Technology plays a role in broadening access to banking. Mobile networks are accelerating the uptake of financial services throughout the developing world. The concept of mobile banking has taken root in the Philippines, South Korea and Africa.

Vodafone's M-Pesa mobile money transfer service, launched in Kenya last year, allows people to open an account and deposit cash through mobile phones. Account holders can send money to other mobile users by text message. The service now has more than 1.6m subscribers.

Another innovative model comes from South Africa, where Wizzit offers services using mobile phones as the channel through which clients sign up and access accounts. The bank has developed technology that can handle large transaction volumes and can be used by other institutions.

"The unbanked are typically rurally based, and the cost of servicing these people through traditional bank branches is so high, the revenue model simply does not work," says Brian Richardson, chief executive of Wizzit.

Supporting this view is a recent report by the Consultative Group to Assist the Poor, a consortium of development agencies. The report found that it costs at least 50 per cent less to serve customers using mobile technology than to offer services through banking models.

Banks can potentially market mobile banking services to mainstream customers, too. "Mobile will be the next major wave in the payments space," says Mr Richardson. "Although our focus is on the unbanked, mobile banking makes sense for everyone."

* The Early Experience with Branchless Banking, CGAP, 2008