The mobile money market in sub-Saharan Africa is expected to double by 2019, but potential for even greater development is held back by lack of interoperability between operators and restrictions on cross-border transactions, Frost & Sullivan reports.

Concerns about security and reliability of mobile money transfers and mobile payments, particularly in markets with intermittent network access, will also challenge market development, according to a report in Finextra.

Frost & Sullivan analyzed mobile money transfers and mobile payments for selected countries in sub-Saharan Africa. The market earned revenues of $655.8 million in 2014 and it’s estimated this will reach $1,319.8 million in 2019, according to the report.

Experts at Mondato, a global advisory company on mobile financial services, said in November that the African mobile money scene could grow significantly in the next four years, with person-to-business transactions in Kenya, Nigeria, South Africa and Ghana poised to hit the $900 billion mark by 2018, ITWebAfrica reports.

Mobile network operators are taking advantage of the growing popularity of mobile money to boost average revenue per user and counter the increasing pressure on voice revenues, Finextra reports.

The mobile money transfer market is still relatively new, and dominated by mobile money transfers between subscribers, according to Frost & Sullivan Analyst Lehlohonolo Mokenela. “There are, however, early signs of agreements to enable inter-operator mobile money transactions that will allow customers to complete transfers across national and global operators,” he said, according to Finextra.