Mckinsey says that two billion individuals and 200 million micro, small, and midsize businesses in emerging economies today lack access to savings and credit, stunting economic growth.

The company believes that digital finance — payments and financial services delivered via mobile phones and the Internet — could transform the lives and economic prospects of individuals, businesses, and governments across the developing world.

McKinsey conducted a range of economic modelling, interviews and field visits to quantify its forecasts. The research estimates that digital finance could provide access to 1.6 billion unbanked people, more than half of them women. An additional $2.1 trillion of loans to individuals and small businesses could be made sustainably, as providers gain newfound ability to assess credit risk for a wider pool of borrowers. Governments could gain $110 billion per year by reducing leakage in public spending and tax collection.

Providers of financial services also stand to save $400 billion annually in direct costs by shifting from traditional to digital accounts, which can be 80 to 90 percent less expensive to service. By expanding their customer base, providers increase revenue opportunities and could sustainably increase their balance sheets by as much as $4.2 trillion, says McKinsey.

The report describes mobile phones as the 'game-changer' that could make all this happen, pointing out that in 2014, nearly 80% of adults in emerging economies had a mobile phone, while only 55% had financial accounts.

"To capture the opportunity, businesses and government leaders will need to make a concerted and coordinated effort," states the report. "Rather than waiting a generation for incomes to rise and traditional banks to extend their reach, emerging economies have an opportunity to use mobile technologies to provide digital financial services for all, rapidly unlocking economic opportunity and accelerating social development."