The installed base of mobile point-of-sale devices is set to increase fivefold over a five-year forecast period, reaching the 51 million mark in 2019, or 46 percent of the overall POS market, according to a new report from ABI Research.

The increase in uptake is not just being driven by micro-merchant adoption, as mPOS vendors are increasingly focused on mPOS penetration higher up the value chain, the firm said in a press release. Other mid-sized merchants and even large retailers are looking toward mPOS to provide new acceptance capabilities, enablement or extension of added value services, while improving in-store mobility levels.

Questions remain around the business viability of mPOS and whether it can be a profitable and sustainable business, ABI said in the release. Which vendor type is most capable of making a success out of mPOS is still up for debate.

ABI noted recent investment news that shows potential growth in the market despite some uncertainty. Provider iZettle is the most recent vendor to attain a $56 million financial injection with POWA, another vendor who in 2013 received $76 million in outside funding. Although these seem like high-value investments into a market which is still to find its feet, investors are not just capitalizing on revenues generated by mPOS devices and transactions, ABI said in the release. The bigger ecosystem picture includes e-commerce, added value and cash register platforms.

"The mPOS market does present a substantial opportunity for not only the expansion of point-of-sale solutions by those vendors already active but also by new OTT players who could come into the payments space using mPOS as an entrance point," Phil Sealy, senior analyst at ABI and the report's author, said in the release. "There has been much said about the cannibalization of the traditional POS market, but ABI Research believes that both traditional POS and mPOS can grow together in tandem, co-existing, expanding the presence of digital payment acceptance. There will always be a need for traditional POS solutions driven by large fixed-lane checkout applications, but equally there will be merchants looking at simpler cost-effective solutions with added value services."