Mastercard Inc. $MA faces a substantial financial obligation following a UK court decision that found its interchange fees from 1992 to 2008 to be unreasonably high. The collective action, launched in 2016 by former Financial Ombudsman Walter Merricks, accused the payments company of charging fees that inflated retail prices nationwide. The court found that these charges were indirectly passed on to consumers, impacting not only Mastercard users but also those paying with other methods, including Visa $V.