Merchant Customer Exchange (MCX), a retailer-led mobile wallet initiative, has announced a new technology partner and unveiled two more merchants among its ranks.

US-based FIS is to provide MCX with payment processing, routing and settlement for mobile commerce transactions when the service goes live.

FIS’ technology, says MCX, will “seamlessly integrate” with mobile wallet software developed by Amsterdam-headquartered Gemalto. MCX announced Gemalto as a partner in April.

“Today’s consumers are increasingly mobile centric and expect to leverage their mobile devices to perform a wide variety of financial services transactions,” said Nancy Langer, EVP, Money Movement, FIS. “FIS is investing in true payments innovation that creates new revenue opportunities for our clients while delivering a functionally rich experience for the customers they serve. “

Kohl’s and Couche-Tard, which rank 20th and 76th respectively on the National Retail Federation’s list of top 100 US merchants by revenue, have also been unveiled as MCX partners.

With the two latest additions, MCX now counts eight of the top 20 merchants (by revenue) as its members. From the top-100 list compiled by the National Retail Federation, more than a fifth has now signed up to the mobile wallet initiative.

MCX members include Wal-Mart, Phillips 66, Gap, 7-Eleven, Best Buy, Target and Dunkin’ Donuts.

MCX says its members, when combined, operate nearly 90,000 stores and process more than $1 trillion in payments annually.

The venture was unveiled in August last year.