Credit-card companies are hiking a range of fees that U.S. merchants will pay to process transactions, a move likely to inflame already fractious relations between many businesses and card networks, the Wall Street Journal reported. Visa Inc. and Mastercard Inc., the two biggest U.S. card networks, are preparing increases to certain existing fees that will kick in this April. Some of the changes relate to so-called interchange fees. Card networks set the price of these fees, which merchants pay to banks when consumers shop with the cards they issue. Also due to rise are fees that card networks charge financial institutions for processing card payments on behalf of merchants. Merchants often increase the prices consumers pay following such fee increases, in an attempt to protect their own profits. Roughly 1 percent to 2.5 percent of prices for goods and services go to cover card fees.