Price fixing is a restraint of trade prohibitted by federal law. The federal law pre-empts state law, and the states are not at liberty to regulate it with legislation which does not conform to federal law.

The courts have ruled that it does not take much to violate the law. A simple nod of the head or wink of an eye is enough when it is clear that the understanding among the paries to the agreement is to restrain trade. An agreement among members of an occupation not to change their prices even when their prices differ from each other is enough to violate the law. Violation can have some serious consequences.