In times past, Visa and MasterCard were proprietary products of Banks issued and accepted by Banks and merchant customers of banks under rules of organisations owned solely by banks. Times have changed, Visa and MasterCard ownership is open to any person or organisation with money to invest. Any large Merchant with the desire to influence the structure of Visa and/or MasterCard rules, including interchange fees, can buy a sufficient percentage of stock in either or both companies to demand a seat on the board of Directors which includes a voice at the board level on acceptance rules and price. It is mystery to me why Walmart is not yet represented on the boards of Visa and MasterCard.