The purpose of market definition in antitrust law is to identify a grouping of sales such that a single firm who controlled them could maintain prices for a significant time at above the competitive level. The conceptions and procedures that go into “market definition” in antitrust can be...

“Zero-price markets,” wherein firms set the price of their goods or services at $0, have exploded in quantity and variety. Creative content, software, search functions, social media platforms, mobile applications, travel booking, navigation and mapping systems, and myriad other products are...