Monopoly
A market structure where a single seller controls the entire supply, enabling above-competitive pricing.
What is Monopoly?
A monopoly is a market structure in which a single seller controls the entire supply of a product or service with no close substitutes, enabling it to set prices above competitive levels and restrict output to maximize profit. Monopolies arise from barriers to entry such as patents, network effects, or government licenses. They typically produce deadweight loss by reducing output below the socially efficient level, which is why most jurisdictions regulate or prohibit them.
Example
De Beers historically controlled over 80% of the global rough diamond supply, allowing it to set wholesale prices and maintain artificially high consumer prices for decades. Regulatory scrutiny and new supply sources eventually eroded this monopoly power.
Source: CFA Institute — Economics