Control of the production and distribution of a product or service by one firm or a group of firms acting in concert. In its pure form, monopoly, which is characterized by an absence of competition, leads to high prices and a general lack of responsiveness to the needs and desires of consumers. Although the most flagrant monopolistic practices in the United States were outlawed by Antitrust Laws enacted in the late 19th century and early 20th century, monopolies persist in some degree as the result of such factors as patents, scarce essential materials, and high startup and production costs that discourage competition in certain industries. Public monopolies-those operated by the government, such as the post office, or closely regulated by the government, such as utilities-ensure the delivery of essential products and services at acceptable prices and generally avoid the disadvantages produced by private monopolies.
. See also Ameren