In some cases, the Department may use court authorized searches of business, consensual monitoring of phone calls and informants equipped with secret listening devices. The Department may grant immunity to individuals or corporations who provide timely information that is needed to prosecute antitrust violations, such as bid rigging or price fixing. A provision in the Clayton Act also permits private parties injured by an antitrust violation to sue in federal court for three times their actual damages plus court costs and attorneys' fees. State attorneys general may bring civil suits under the Clayton Act on behalf of injured consumers in their states, and groups of consumers often bring suits on their own. Such follow-on civil suits to criminal enforcement actions can be a very effective additional deterrent to criminal activity.
Most states also have antitrust laws closely parallelling the federal antitrust laws.
The state laws generally apply to violations that occur wholly in one state. These state laws are enforced similarly to federal laws through the offices of state attorneys general. The worst antitrust offenses are price fixing and bid rigging. Price fixing occurs when two or more sellers agree that they will increase prices a certain amount, or that they won't sell below a certain price. Bid rigging most commonly occurs when two or more firms agree not to bid against each other to supply products or services to local, state or federal government agencies, or when they agree on the level of their individual bids.