In antitrust terms, a company doesn't have to be the only one that exists to be a monopoly. Microsoft was ruled a monopoly in United States v. Microsoft Corp d

In antitrust terms, a company doesn't have to be the only one that exists to be a monopoly. Microsoft was ruled a monopoly in United States v. Microsoft Corp despite the existence of Linux, BSD, Solaris, and other alternatives. The FTC is currently accusing Amazon of being an unlawful monopoly despite the existence of thousands of small competitors.