A monopoly market is a market structure where a single seller or producer assumes a dominant position in an industry or sector. In a purely monopolistic model, the monopoly firm can restrict output, raise prices, and enjoy super-normal profits in the long run. A monopolistic market is the opposite of a perfectly competitive market, in which an infinite number of firms operate. Key features of a monopoly market include:

• Single seller: A monopoly exists when one supplier provides a particular good or service to many consumers.
• Price maker: The monopoly that sets the price and supply of a good or service is called the price maker. A monopoly is a profit maximizer because by changing the supply and price of the good or service it provides, it can generate greater profits.
• Barriers to entry: Monopolies are characterized by high barriers to entry, such as significant startup costs, patents, copyrights, and resource ownership.

Monopolies are discouraged in free-market economies as they stifle competition and limit substitutes for consumers. In the United States, antitrust legislation is in place to restrict monopolies, ensuring that one business cannot control a market and use that control to exploit its customers. Without competition, monopolies can set prices and keep pricing consistent and reliable for consumers. Monopolies enjoy economies of scale, often able to produce mass quantities at lower costs per unit. Standing alone as a monopoly allows a company to securely invest in innovation without fear of competition.