A U.S. District Court judge has sided with retailers seeking a lower cap on fees charged by banks for debit card transactions.

According to Reuters, Judge Richard Leon of the U.S. District Court for the District of Columbia ruled this week that the Federal Reserve had ignored the intent of Congress when it capped the fees banks can charge retailers when their customers use debit cards. The 2010 Dodd-Frank law called for limits on those fees. Retailers have since argued that the Fed’s cap of 21 cents per transaction was higher than Congress intended.

The ruling, which will lead to lower interchange rates for billions of debit card transactions annually, caused the shares of Visa and MasterCard to plunge 11% and 6%, respectively. The two companies had set the fee level that banks charge retailers for using their networks.

The 21-cent cap likely will remain in place until the Fed rewrites its rules or appeals the decision, Reuters reported.