The real winners under the Credit Card Competition Act would be big box retailers, Scott Zahnle, CEO of Greater Iowa Credit Union wrote in The Des Moines Register this week. 

"There’s no real way to sugarcoat it: The Marshall-Durbin interchange bill would be a disaster for almost everyone it affects, especially consumers, community-based financial institutions, and small businesses," he wrote. "Consumers will lose when retailers that are more concerned about their bottom line choose the cheapest possible option for their routing network, without regard for consumer choice or the safety and security of consumers’ sensitive financial data."

Zahnle goes on to add that--despite the exemption for institutions $100 billion in assets--smaller institutions would certainly be affected due to increased risks for the card network. 

"The real winners in this bill are the big box retailers — the ones that already currently pose an existential threat to Main Street," he wrote.