This paper provides empirical evidence of a well-known theoretical concern that market failures in two-sided markets are hard to identify and correct. We study the reactions of banks, merchants, and consumers to Dodd-Frank’s Durbin Amendment that lowered interchange fees on debit card transactions. Banks recouped a significant portion of their losses by charging consumers for products that they previously provided for free on the subsidized side of the two-sided market. The accelerated adoption of credit cards with higher interchange fees likely diminished—if not eliminated—merchants’ savings. These effects impede the regulation’s stated objective of enhancing consumers’ welfare through lower retail prices.

Recent influential work finds large increases in inequality in the United States based on measures of wealth concentration that notably exclude the value of social insurance programs. This paper shows that top wealth shares have not changed much over the last three decades when Social Security is properly accounted for. This is because Social Security wealth increased substantially from $7.2 trillion in 1989 to $40.6 trillion in 2019 and now represents nearly 50% of the wealth of the bottom 90% of the wealth distribution. This finding is robust to potential changes to taxes and benefits in response to system financing concerns.