When Theoretical Rigor Misses Reality: Why Interchange-Fee Caps Won’t Benefit Consumers
Interchange fees charged by payment networks have in recent years been one of the most heated and persistent battles in financial regulation. These fees—typically 1-3% of credit-card transaction value in the United States—are charges that banks impose on merchants for processing credit- and debit-card transactions. What started as an obscure technical detail has exploded into a multi-billion-dollar policy dispute, involving massive litigation, regulatory intervention worldwide, and fierce debates among merchants, banks, payment networks, and policymakers.
The controversy centers on a fundamental conflict that arises within payment networks in their role as two-sided markets. Merchants argue that interchange fees are excessive and anticompetitive, forcing them to absorb significant costs or pass them on to consumers through higher prices. Banks counter that interchange fees fund essential infrastructure, fraud protection, and rewards programs that make electronic payments secure and attractive. This tension has sparked global regulatory responses, from the EU’s comprehensive fee caps to the Durbin amendment’s debit-card restrictions, to the proposed Credit Card Competition Act.
A recent working paper by Robert Hunt, Konstantinos Serfes, and Yin Zhang claims that capping interchange fees would benefit all consumers, even credit-card users whose rewards might decrease. Their conclusion contradicts substantial evidence from real-world implementations of interchange-fee caps. While mathematically elegant, the paper’s theoretical model relies on simplifying assumptions that obscure the complex realities of payment markets, and lead to policy recommendations that could harm the consumers they aim to help.