Walmart is one of several high-profile retailers that belong to MCX, a consortium of retailers that have partnered together to create their own mobile payments service called CurrentC. Due to this commitment, the big-box retailer has opted against supporting Apple Pay in its stores. A new report offers a big reason why: high credit card transaction fees.

Re/code offers some insight this weekend into why Walmart “will never accept Apple Pay,” with a big part of the reason being that Walmart believes that the fees merchants are required to pay banks when a credit card is swiped in their stores is too high. Meanwhile, MCX’s CurrentC has payment options that carry lower fees than credit card purchases.

Given that Apple Pay supports both Visa and MasterCard, which set the fees that Walmart and other MCX retailers believe is too high, the report claims that Walmart feels the iPhone-based payments service does not support its fight for the payments fee structure to be changed.

“Since Apple Pay supports Visa and MasterCard credit cards, Walmart and other MCX retailers believe the iPhone-based payments service just perpetuates the traditional payments fee structure they despise,” claims Re/code. “The MCX’s CurrentC app, on the other hand, favors transactions funded by store-branded cards or a connection with a customer’s checking account — all of which carry lower fees than credit card purchases.”

Look no further than the video below in which Walmart assistant treasurer Mike Cook and Visa executive Jim McCarthy had a heated discussion about credit card fees at a recent payment conference called Money2020 to see the tension between the retailer and credit card networks.

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Merchant Customer Exchange (MCX) consists of several other retailers, including CVS, Rite Aid, 7-Eleven, Best Buy, Lowe’s, Publix, Sears, Shell, Sunoco and Target. MCX’s CurrentC has an expected launch date of early 2015.

Walmart did not provide comment.