No, monopolies aren't necessarily illegal in the USA. But they can be depending on the behavior of a monopolist. From http://www.girardgibbs.com/antitrust-mono

No, monopolies aren't necessarily illegal in the USA. But they can be depending on the behavior of a monopolist. From http://www.girardgibbs.com/antitrust-monopoly/ http://www.girardgibbs.com/antitrust-monopoly/: > Monopolies are illegal if they are established or maintained through improper conduct, such as exclusionary or predatory acts. This is known as anticompetitive monopolization.