Group boycott

In competition law, a group boycott is a type of secondary boycott in which two or more competitors in a relevant market refuse to conduct business with a firm unless the firm agrees to cease doing business with an actual or potential competitor of the firms conducting the boycott. It is a form of refusal to deal, and can be a method of shutting a competitor out of a market, or preventing entry of a new firm into a market.

In the United States, such conduct can be held to violate the Sherman Antitrust Act. Depending upon the nature of the boycott, the courts may either apply the rule of reason, or hold that the boycott is illegal per se. It may also be considered a form of civil conspiracy.