A Federal Reserve cap on fees charged for processing debit-card transactions has been tossed out by a federal judge in Washington, who agreed with retailers that the Fed went too easy on big banks in 2011 when it set the limit at 21 cents per transactions.

The ruling Wednesday addresses fees that most consumers are unaware of — but which are charged to merchants each time a customer swipes a debit card at a check-out counter.

Retailers cheered the decision by U.S. District Judge Richard Leon and banks decried it. The Fed didn’t disclose whether it would appeal the ruling.

Leon held off putting his ruling into effect pending a hearing Aug. 14, but wrote that the Fed “has clearly disregarded Congress’ statutory intent by inappropriately inflating all debit-card transaction fees by billions of dollars.”

The dispute stems from an amendment to the 2010 Dodd-Frank financial reform law, which required the fees reflect the actual processing costs. The Fed’s staff recommended cutting the fee from 44 cents to just 12 cents, but backed off after heated protests from the financial industry.