About half a million South Africans now use their mobile phones as a bank. Besides sending money to relatives and paying for goods, they can check balances, buy mobile airtime and settle utility bills. Traditional banks offer mobile banking as an added service to existing customers, most of whom are quite well off. But Wizzit, and to some extent First National Bank (FNB) and MTN Banking (a joint venture between Standard Bank and a mobile-phone network), are chasing another market: the 16m South Africans, over half of the adult population, with no bank account.