What is an example of a firm that operate under monopoly market?

Question

What is an example of a firm that operate under monopoly market?

Answer 1

KCOM (Kingston Communications) on the provision of telephone and broadband services in Hull and the surrounding areas.

Answer 2

A monopoly exists when a specific individual or enterprise has sufficient control over a particular product or service to determine significantly the terms on which other individuals shall have access to it.  Monopolies are characterized by a lack of economic competition for the good or service that they provide and a lack of viable substitute goods.

Examples;

AT&T was.... but they were broken up in 1982.

More recently Microsoft has been sued because of the monopolistic way a new computer comes outfitted with Mocrosoft's operating system already installed, seemingly to the exclusion of other types of operating systems that might be available, if any.