ExxonMobile has signaled its interest in promoting mobile payments by joining the Merchant Customer Exchange. The member-owned MCX is building a merchant-controlled mobile payments infrastructure that will compete with initiatives such as Isis and Google Wallet.

Besides ExxonMobile, Giant Eagle, Kum&Go and Rite Aid Corp. are also joining MCX, whose existing members include Walmart, Kmart, Olive Garden and Southwest Airlines.

The addition of the new members takes the total number of merchants participating in MCX to more than 50. The members represent in excess of 100,000 locations and more than $1 trillion in payments annually, MCX said.

"We are seeing tremendous interest and momentum with new merchants, large and small, coming on board to work together to offer a mobile commerce solution that will best serve the needs of customers and merchants alike," MCX CEO Dekkers Davidson said in a news release.

MCX was founded in 2012 and has offices in Dallas and Boston.

Learn more about mobile/digital wallets and retail.