Mark W. Nelson


T: +1 202 974 1622
F: +1 202 974 1999

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Mark W. Nelson is a partner based in the Washington, D.C. office.

Mr. Nelson’s practice focuses on U.S. and EU antitrust matters, with an emphasis on merger cases. His U.S. practice background includes extensive merger work and antitrust counseling, and litigation experience in both civil and criminal matters, as well as in FTC administrative proceedings. His European practice involves merger cases at both the EU and Member State levels, and defending actions involving alleged restraints of trade and abuses of dominant position. He has also been actively involved in litigation, investigations, and counseling in matters involving the intersection of antitrust and intellectual property law, in particular in the context of patent pools and standards-setting.

Mr. Nelson has represented clients in a wide range of industries, including, among others, airlines, aluminum, cement, computer networking equipment, consumer products, industrial equipment, fiber optic systems and components, financial information services, foreign exchange trading, oil and gas, petrochemicals, pharmaceuticals, software, travel services, and wireless telephony. Mr. Nelson is distinguished as one of the leading antitrust lawyers by Chambers Global, Chambers USA, The Best Lawyers in America, The Legal 500 U.S. and Global Competition Review’s International Who's Who of Competition Lawyers

Some of the major merger matters that he has been involved in include: AT&T/T-Mobile, BHP Billiton/PotashCorp, Nortel/Avaya, EMC/Data Domain, Kindred Healthcare/RehabCare, Assured Guaranty/FSA, Nasdaq/Instinet, Conoco/Phillips Petroleum, Alcoa/Reynolds, Dow/Union Carbide, and Lafarge/Blue Circle.

In antitrust litigation matters, representations include Lafarge in successfully eliminating it as a defendant in class action litigation alleging a price fixing conspiracy, Broadcom in appellate victory against Qualcomm in monopolization suit involving standards setting issues, UTAC in defending a patent litigation suit filed by Tessera, Aspen Technology in administrative litigation initiated by the FTC to challenge Aspen Technology’s acquisition of Hyprotech, and Polimeri Europa and Syndial in civil litigation alleging price fixing related to several synthetic rubber products. Mr. Nelson also represents clients in criminal and civil antitrust investigations by the Department of Justice and the Federal Trade Commission.

Mr. Nelson is part of the leadership of the ABA’s Antitrust Section, as Vice Chair of the Books & Treatises Committee and Vice Chair of the Intellectual Property Owners Association Antitrust & Competition Law Committee. He was also on the Editorial Board for the most recent release of the ABA’s antitrust treatise, Antitrust Law Developments. He has written articles and contributed to a variety of publications, including Global Competition Review, Competition Law of the European Community, Antitrust Law Developments, European Merger Control Law (chapter on U.S. merger control), and International Computer Law. He is also a frequent speaker on antitrust law, including on the intersection of antitrust and intellectual property law, the merger review process, and compliance training programs.

Mr. Nelson joined the firm in 1993 and became a partner in 2002. He was resident in the Brussels office for three years. Mr. Nelson received a J.D. degree from Harvard Law School in 1992 and an undergraduate degree from Cornell University in 1989. Prior to joining Cleary Gottlieb, he served as a law clerk to Judge Andrew J. Kleinfeld of the U.S. Court of Appeals for the Ninth Circuit.

Mr. Nelson is a member of the Bars in New York and the District of Columbia.

Honors and Distinctions

Chambers Global - Competition/European Law (Expert Based Abroad): Belgium. Competition/Antitrust (Foreign Expert): United States.

Chambers USA - Antitrust.

The Legal 500 U.S. - Antitrust.

The Best Lawyers in America - Litigation: Antitrust.

Global Competition Review’s International Who's Who of Competition Lawyers


  • Harvard Law School
    (J.D., 1992)
  • Cornell University
    (B.S., 1989)

Bar Admissions

District of Columbia - 1994
New York - 1993

Areas of Law