Understanding Marginal Costs in Two-Sided Markets: Implications for Debit Card Interchange Regulation

Abstract

The paper reviews the economic literature’s treatment of marginal costs in two-sided markets is discussed below with particular emphasis on literature discussing the payment card market. An underlying issue explored in this paper is the how financial reform legislation’s use of the term “incremental costs” compares with the use of the term in the literature and with the definition of marginal cost. Also discussed is the significance of the two-sided market phenomena to efficient pricing decisions, the need to consider costs incurred on both sides of the market, and estimates of the marginal cost to banks of processing debit card payments. The paper will conclude with a summary of five key principles that the Federal Reserve should apply when developing their proposed debit card interchange fee regulation.