What Combo of companies ran by a board of trustees that control prices and eliminate competition?

The combination of companies run by a board of trustees that control prices and eliminate competition is known as a "trust." Historically, this term was used to describe monopolistic practices where a group of businesses, often in the same industry, would come together to set prices and limit competition, such as the Standard Oil Trust in the late 19th century. These trusts would manipulate market conditions to their advantage, leading to regulatory interventions like the Sherman Antitrust Act in the U.S. to promote fair competition.