Economic Definition of collusion. Defined.
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Term collusion Definition: A usually secret agreement among competing firms (mostly oligopolistic firms) in an industry to control the market, raise the market price, and otherwise act like a monopoly. The reason for the secrecy is that such behavior is illegal in the United States under antitrust laws. Collusion is a characteristic trait of oligopolistic industries. Intense competition and interdependent decision-making encourages oligopolistic firms to cooperate. One way to lessen the competition among an oligopolistic rival is to join forces through collusion. (The other way is through merger, but that's another entry.)