The number of OEM-Pay contactless users, including Apple Pay, Samsung Pay, and Android Pay, will exceed 100 million for the first time during the first half of 2017 before surpassing 150 million by the end of this year, according to a new report from Juniper Research.

The combined market share of Apple, Samsung, and Google (via Android Pay), increased from 20 percent in 2015 to 41 percent in 2016, as a proportion of total mobile contactless payment users. Juniper forecasts that this will rise to 56 percent by 2021 as the trio's combined user base exceeds 500 million.

The research found that Apple Pay and the alternative wallets that have followed in its wake, are set to establish themselves as the primary contactless mechanisms of choice in the U.S. However, the challenge facing Apple and its rivals is to ensure that the infrastructure is in place for consumers to make in-store payments.

"We believe that as contactless usage gains traction and consumers/merchants recognise the speed and convenience it offers, then, as in European markets, there will be a further and significant increase in availability at the point-of-sale," Nitin Bhas, Juniper's research author, said in a statement. 

Juniper's research also found that 2015 and 2016 were watershed years for HCE in terms of commercial service rollouts. Juniper estimates that at least 194 banks had introduced such services by the end of 2016. Juniper expects PayPal, already near ubiquitous in the online space, to rapidly deploy a portfolio of contactless payment and loyalty products that will enable it to compete effectively for market share.