Merchants have long accused Visa and Mastercard of charging inflated swipe fees, or interchange fees, when shoppers used credit or debit cards, and barring them through "anti-steering" rules from directing customers toward cheaper means of payment.

Visa (V.N), and Mastercard (MA.N),  reached an estimated $30 billion settlement to limit credit and debit card fees for merchants, with some savings likely to be passed on to consumers through lower prices.

The antitrust settlement announced on Tuesday is one of the largest in U.S. history, and if it receives court approval would resolve most claims in nationwide litigation that began in 2005.

Some critics believe it may not go far enough, saying the savings would be temporary and fees would remain high.

Merchants have long accused Visa and Mastercard of charging inflated swipe fees, or interchange fees, when shoppers used credit or debit cards, and barring them through "anti-steering" rules from directing customers toward cheaper means of payment.

Swipe fees typically include small fixed fees plus a percentage of total sale amounts, and average about 1.5% to 3.5% per transaction according to Bankrate.com.

Under the settlement, Visa and Mastercard would reduce swipe rates by at least four basis points - 0.04 percentage points - for three years, and ensure an average rate that is seven basis points below the current average for five years.

Both card networks also agreed to cap rates for five years and remove anti-steering provisions.

Merchants will have more discretion to offer discounts, or impose surcharges on cards with higher interchange fees.

Many already warn customers at checkout they will pay more using cards instead of cash.

The fee rollbacks and caps alone are worth $29.79 billion, according to court papers, and Visa estimated that small businesses comprise more than 90% of the settling merchants.

Visa and Mastercard denied wrongdoing in agreeing to settle.

In separate statements, Visa's North American president Kim Lawrence said the accord addressed "true pain points" identified by small businesses, while Mastercard General Counsel Rob Baird said it gave businesses "substantial certainty."