This chapter examines the enforcement campaign against manipulation of interest rate and foreign exchange benchmarks by traders and other employees of global banks. After reviewing the history, functioning, and weaknesses of LIBOR, the world’s most important interest rate benchmark, the chapter relates how the banking industry, banking regulators, and central bankers responded ineffectively to signs of LIBOR manipulation that emerged in 2008. By contrast, robust enforcement actions spearheaded by the U.S. Department of Justice and the Commodities Futures Trading Commission, beginning with the Barclays case in 2012, attracted worldwide attention. They led directly to parliamentary investigations, leadership turnover at some banks, and significant domestic and international benchmark reforms, culminating with an industry-wide shift away from LIBOR toward more reliable indices. Likewise, the foreign exchange manipulation scandal and related prosecutions led to the adoption of international reforms. In both cases, several individuals were also charged criminally, most notably UBS trader Tom Hayes. By using its authority over global banks to protect the integrity of widely used financial benchmarks that have the characteristics of public goods, U.S. actions benefited users of these benchmarks around the world.