In economics, a cartel is a group of formerly independent companies who overtly agree to work together. The objectives of cartels are to increase their profits or to stabilize market sales. They do this by fixing the price of goods, by limiting market supply or by other means. Monopolies are not cartels, because in a monopoly there is only one independent company. Cartels are bad for the economy in general and for their customers who are overcharged. Cartels usually occur in oligopolies, where there are a small number of players that control the majority of supply in a market.