What is the term for exclusive control over a commodity or service in a market that can manipulate prices?

The term for exclusive control over a commodity or service in a market that can manipulate prices is monopoly. A monopoly occurs when a single company or entity is the sole provider of a particular product or service, allowing it to dictate pricing and supply without competition. This lack of competition often leads to higher prices and reduced output, as the monopolistic entity prioritizes profit maximization over customer welfare or market efficiency.

In contrast, an oligopoly involves a market structure with a small number of firms that have significant market power, which can lead to competitive behaviors like price-fixing; however, they do not have exclusive control. A cartel refers to a formal agreement between competing firms to control prices or production, which can mimic monopolistic traits but is not the same as having sole control. A duopoly, meanwhile, is a specific type of oligopoly involving only two firms; while these firms can have substantial market influence, they still do not possess the exclusive control characteristic of a monopoly.