Annual retail payments on mobile handsets and tablets will reach $707 billion, or 30 percent of all e-Retail by 2018, compared with 11 percent in 2012 and 15 percent in 2013, according to a report by Juniper Research.

Total global eRetail spend will increase from just under $1.2 trillion in 2013 to $2.3 trillion in 2018, representing an average annual increase of 14.3 percent, the U.K.-based consultancy estimated. In 2013, mobile retail purchases totaled $182 billion.

To keep up with the trend, leading retailers are increasingly developing strategies built around mobile, using mobile as a hub for facilitating payments, product discovery and customer retention, according to Juniper Research's report "Mobile Payment for Digital & Physical Goods: Opportunities & Forecast 2014-2018."

Consumers who own both mobiles and tablets prefer to browse for products on mobiles while paying on a tablet, Juniper Research said. This meant that by the end of 2013, global per month mobile retail spending on tablets had overtaken that on handsets.

There is a growing trend toward "showrooming," where customers examine in-store retailer products while browsing prices at online retailers on their mobile.

Retailers need to respond to this behavior by equipping sales staff with tablets that offer price matching, report author Windsor Holden argued.

For example, Target has equipped sales assistants with iPads so they can compare prices for customers. Target will then match the prices for identical products from Amazon.com, BestBuy.com, Walmart.com, local retail stores and its own website, Target.com.

Mobile POS tablets can be used to allow customers to complete their purchase transactions immediately rather than have to stand in line at checkouts, Holden said.

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