The imposition of effective cartel sanctions is shaped by the policy of and guidelines from enforcing authorities, such as the European Commission, as well as the Union Courts. The application of the 2006 Guidelines on Fines has been guided by the jurisprudence of the Union Courts. The Courts have in general upheld the fining methodology expressed in the guidelines and have clarified the way it should be applied in specific situations. The fact that the system of setting and reviewing EU competition fines was found lawful adds to the legitimacy of such fines and their enhanced deterrent effect. The aim of authorities and reviewing courts is to impose adequate and deterrent sanctions, while respecting the rights of defence of the undertakings.

The Directive on Damages Actions 104/2014 (the Damages Directive) has laid down a common European framework for the regulation of competition damages actions. It establishes fundamental principles, such as the right to compensation and the joint liability of antitrust infringers for such compensation. However, it explicitly avoids defining causation, thus leaving it to the domestic laws of member states. The only limit set by the EU law is the observance of the principles of equivalence and effectiveness, in line with what was already disposed by the CJEU in Manfredi. However, there are some principles addressing causation that can be found in European law and case law.