In 2020-21, lawsuits have been filed raising antitrust complaints in state and federal district court by coalitions of state attorneys general, the U.S. Department of Justice, the Federal Trade Commission, and private firms against four large American technology companies, Amazon, Apple, Facebook, and Google. In this paper, I review the complaints and the criteria that will be used by judges and juries to assess whether Amazon, Apple, Facebook, and Google engaged in anticompetitive conduct. The courts will use the consumer welfare standard, rule of reason analysis, and other legal precedents in antitrust law and competition policy to prove harm. In each case, the courts will ask litigants to present evidence and develop theories of market definition, market concentration, market structure, and exclusionary agreements for different components of the digital economy.
