A cartel is a formal (explicit) "agreement" among competing firms. It is a formal organization of producers and manufacturers that agree to fix prices, marketing, and production. Cartels usually occur in an oligopolistic industry, where the number of sellers is small (usually because barriers to entry, most notably startup costs, are high) and the products being traded are usually homogeneous. Cartel members may agree on such matters as price fixing, total industry output, market shares, allocation of customers, allocation of territories, bid rigging, establishment of common sales agencies, and the division of profits or combination of these.