A group of large retailers have teamed up and are on the brink of announcing a rival to Google Wallet, Google's [Goog] mobile payment system, setting the stage for a fierce battle in the fledgling digital wallet business, reports indicated Wednesday.

Wal-Mart Stores Inc. [WMT], Target Corp. [TGT], 7-Eleven Inc., and Sunoco Inc. [SUN] are poised to announce their joint-venture, Merchant Customer Exchange (MCX), which is designed to rival the Google Wallet payment system that launched on Android-powered phones last year, the Wall Street Journal revealed.

However, at present, there is is no known launch date, with the consortium understood to be searching for a CEO to helm MCX.

When it does launch, MCX will join the multibillion dollar race to develop mobile phone payment systems, which aim to do away with cash and card transactions.

According to a report by Gartner, a market research firm, mobile payment transactions are expected to be worth an estimated $600 billion by 2016.

Apple's upcoming iPhone 5 is rumored to contain Near Field Technology (NFC) chips that will work with the company's Passbook wallet system, another contender set to enter the mobile payment battle.

The venture by Wal-Mart and its partners comes after a protracted battle between retailers and Visa and MasterCard over the transaction fees that the credit card companies charge retailers for accepting their credit and debit cards.

The Merchants Payments Coalition (MPC), which represents retailers, says the fees levied on American supermarkets, stores and gas stations by Visa and MasterCard are up to three times more than similar fees in other parts of the world, inflating prices for U.S. consumers.

Last month Visa [V], MasterCard [MA] and several major banks agreed to pay U.S. retailers a record $7.25 billion in penalties to settle a long-running lawsuit that alleged the card giants conspired to fix so-called "swipe fees" paid by shops and supermarkets.

Several of the country's largest retailers and industry groups have rejected the deal.

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