Germany
Federal Cartel Office (Bundeskartellamt)
The Bundeskartellamt (Federal Cartel Office) is an independent higher Federal authority which is responsible to the Federal Ministry of Economics. The main task of the Bundeskartellamt is to apply the Act Against Restraints of Competition (ARC), which was enacted for the protection of competition and came into force on 1 January 1958.

Monopolkommission (This page is only available in German)
Der gesetzliche Auftrag der Monopolkommission umfasst: 1) Regelmäßige Beurteilung des jeweiligen Standes und der absehbaren Entwicklung der Unternehmenskonzentration in Deutschland unter wirtschafts-, insbesondere wettbewerbspolitischen Gesichtspunkten. 2) Würdigung der Vorschriften über die Zusammenschlusskontrolle. 3) Stellungnahme zu aktuellen wettbewerbspolitischen Fragen. Die Monopolkommission umfasst fünf Mitglieder, die über besondere volkswirtschaftliche, betriebswirtschaftliche, sozialpolitische, technologische oder wirtschaftsrechtliche Kenntnisse und Erfahrungen verfügen müssen. Die Mitglieder der Monopolkommission werden auf Vorschlag der Bundesregierung durch den Bundespräsidenten für die Dauer von vier Jahren berufen.

Regulatory Authority for Telecommunications and Posts (Regulierungsbehörde für Telekommunikation und Post)
The former monopoly operators in the postal and telecommunications markets, Deutsche Post AG and Deutsche Telekom AG, will be able to maintain their dominant position long after market liberalisation. The core task of state regulation must therefore be to keep a check on each dominant provider's position in the market and to create a level playing field to protect the new entrants. The Regulatory Authority for Telecommunications and Posts was therefore set up as provided for by the Telecommunications Act, in force since 1 August 1996. It is a higher federal authority within the scope of business of the Federal Ministry of Economics and Labour. The Regulatory Authority superseded the Federal Ministry of Posts and Telecommunications and its subordinate Federal Office. The Regulatory Authority, which took up its work on 1 January 1998, is tasked with promoting the development of the postal and telecommunications markets through liberalisation and deregulation. It is equipped with effective procedures and instruments with which to enforce the regulatory aims. These include information and investigative rights as well as a set of sanctions.

European Union 

European Union / Competition Directorate General

The mission of Competition Directorate General is to enforce the competition rules of the Community Treaties in order to ensure that competition in the EU market is not distorted, thereby contributing to the welfare of consumers and the competitiveness of the European economy.

 USA

Department of Justice / Antitrust Division

The mission of the Antitrust Division is to promote and protect the competitive process — and the American economy — through the enforcement of the antitrust laws. The antitrust laws apply to virtually all industries and to every level of business, including manufacturing, transportation, distribution, and marketing. They prohibit a variety of practices that restrain trade, such as price-fixing conspiracies, corporate mergers likely to reduce the competitive vigor of particular markets, and predatory acts designed to achieve or maintain monopoly power.

OECD

OECD - Competition/Antitrust Policy Division

Well-designed competition law, effective law enforcement and competition-based economic reform promote increased efficiency, economic growth and employment for the benefit of all. OECD work on competition law and policy actively encourages decision-makers in government to tackle anti-competitive practices and regulations and promotes market-oriented reform throughout the world.