Five years ago, Congress finally brought competition to the more than $50 billion market for processing debit-card purchases.

Visa and MasterCard had been price-fixing the fees that banks charge merchants to process the transaction when a customer swipes a debit card to pay for everything from lunch to laundry soap.

These exorbitant "swipe fees," dictated by just two companies, raised the price of everything consumers buy, even if they don't use a card.

That hurts most the poorest consumers, many of whom don't even use cards, according to a Harvard Business School study, and can't even take advantage of benefit programs.

Yet consumers know little about this rigged market, and that is the way the banks like it.

Besides raising prices, swipe fees hurt small businesses, from the convenience store on the corner to the diner downtown, many of whom have seen the fees swell into their second-largest operating cost, after only labor.

As these onerous, unfair swipe fees make it harder for retailers to expand and hire, the fees hurt the entire economy as it struggles to grow.

Even the modest reform that Congress passed saved consumers $6 billion, according to an economist's study, and supported more than 37,000 jobs in its first year alone.

For instance, Visa and MasterCard paid their member banks to block other companies from processing debit transactions for merchants.

Under a reform, known as the Durbin Amendment, Congress said there must be at least two competitors available to handle transactions, meaning lower costs.

As for price-fixing fees, reform limits this and, for the first time, gives banks an incentive to compete on these fees.

So far few have elected to compete freely because — even after reform and the new limits — they're still able to charge almost a quarter for a transaction that costs them only 4 cents, according to the Federal Reserve.

That means they're still raking in an average 500-percent markup on each transaction they process, according to their own figures filed with the Fed.

But the big banks are claiming even these modest reforms are ravaging them.

Earlier this fall they persuaded members of the House Financial Services Committee to narrowly pass the Choice Act, which in repealing the Dodd-Frank financial-reform law would also repeal the Durbin Amendment to the law.

For retailers, though, it's the "No-Choice Act." The repeal of Durbin would mean a return to the rigged market of the past, void of any competition, bad for consumers and every business but the banks that would once again rake in even more enormous profits.

That's why retailers from around the country are flying to Washington on Wednesday to talk to members of Congress about the importance of a free markets for debit cards.

We've come a long way from the bad old days of the meat-packing and railroad and steel trusts of the early 1900s.

We broke them up because their collusion thwarted the rise of competitors and hurt the public with higher prices and shoddy, unsafe products.

But clearly we're not finished even now. The banks should be embarrassed by the rigged market in swipe fees, but they are not; so should their advocates, but they're not.

Instead they will continue to gouge merchants and consumers until competition finally comes to the market, either through legislation or incentives; because 500-percent markups are unheard of in most businesses, and the banks are clearly loath to give them up, no matter what havoc they wreak on consumers and retailers.

That means we need more reform and more competition in the debit market, not less. And in fact, we should bring competition to the credit-card market, untouched by any reform as yet.

Let's embrace free-market principles and make this rigged corner of American business as free and competitive as most of the rest of the economy.

Mr. Spakes is president of the Arkansas Grocers and Retail Merchants Association. Thinking of submitting an op-ed to the Washington Examiner? Be sure to read our guidelines on submissions.