For years, regulators and competition watchdogs have expressed concern about competition in the digital advertising business. They note that digital advertising appears to be dominated by a few dominant firms, such as Google, Facebook, and—to a lesser extent—Amazon. Some claim that this...

Over the past 20 years the consumer payments system has been transformed as electronic payments such as debit and credit cards have rapidly displaced legacy payment systems, especially checks. At the same time, this growth in the use of electronic payments has triggered increasing government...