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Attorney Profile

M. Brian McMahon
Los Angeles, California
phone (213) 628-9800
fax (626) 440-0829
email mbm@brianmcmahonlaw.com


  • Ph.D. Philosophy, University of Wisconsin, 1972
  • J.D. University of California, Los Angeles, 1978


  • Private Practice since 1979
  • Law Clerk to Judge Ozell Trask, United States Court of Appeals for the Ninth Circuit and Central Staff to the Ninth Circuit, 1978-1979
  • Member of the State Bar of California
  • Practice before all Federal and State Courts in California, including U.S. Ninth Circuit Court of Appeals and the Federal Circuit
  • AV Rating from Martindale-Hubbell for over 20 years
  • AVVO Rating
  • Lecturer in Philosophy 1970-1972
  • Assistant Professor of Philosophy 1972-1975, University of Wisconsin-Parkside



  • Recovered $3.5 billion for California natural gas and electricity customers and recovered over $30 million for the City of Long Beach and its natural gas ratepayers in Natural Gas antitrust case and was a member of joint litigation team.
  • Obtained summary judgment dismissing multimillion dollar CERCLA contribution claim against the City of Long Beach.
  • Litigated against major oil companies for conspiracy to underprice crude oil; recovered over $300 Million.
  • Recovered millions of dollars for the State of New Mexico from major oil companies for underpayment of crude oil royalties.
  • Obtained reversal in appellate court of summary judgment against client's Unfair Practices Act claim.
  • Provided assistance to a Federal Interagency Task Force concerning underpayment of federal crude oil royalties.
  • Successful representation of antitrust claims of distributor of baseball equipment against two baseball distributor trade groups.
  • Special assistance to State of California concerning antitrust concerns over the merger of two major oil companies.
  • Represented State of California in successfully urging the U.S. Department of Interior to change its valuation regulations for federal crude oil.


  • United States House of Representatives, Government Management, Information and Technology Subcommittee, Government Reform and Oversight Committee, June 1996.
  • United States House of Representatives, Energy and Mineral Resources Subcommittee, Resources Committee, May 1998 and September 1998.
  • United States Senate, Energy and Natural Resources Committee, June 1998.
  • Hearing before the Honorable George Miller and the Honorable Carolyn B. Maloney, Members of the House of Representatives, July, 1998 concerning regulations proposed by the Minerals Management Service, United States Department of Interior, for the collection of crude oil royalties.
  • United States House of Representatives, Energy and Mineral Resources Subcommittee of the Committee of Resources, June 2001.


  • Beware of Leases that Require Arbitration and Prohibit Class Actions, ROAR (Royalty Owners Action Report), May 2012.
  • Tying Law: The Clash Between the Supreme Court and Lower Courts, COMPETITION, THE JOURNAL OF THE ANTITRUST AND UNFAIR COMPETITION SECTION OF THE STATE BAR OF CALIFORNIA, Vol. 16, No. 2, Fall/Winter 2007.
  • Co-Author, Chapter 9: Antitrust and Unfair Competition in Regulated Industries, Chapter 13: Exemptions, Immunities, and Other Defenses to Antitrust Liability, and Peer Reviewer for CALIFORNIA ANTITRUST AND UNFAIR COMPETITION LAW, IV. Ed., LexisNexis 2009.
  • Authored updates to Chapter 9, CALIFORNIA ANTITRUST AND UNFAIR COMPETITION LAW, IV. Ed., LexisNexis, 2011-2015


  • Lessor/Lessee Allocation of Post-Production Costs: A Survey, National Association of Royalty Owners (ROAR), October 2011.
  • Clayworth v. Pfizer: Rejected the Pass-On Defense, or Did It? Antitrust Section of the Los Angeles County Bar, Panel Moderator, March 2011.
  • How to Avoid Prison, Fines and Damage Awards for Violations of the Antitrust Laws, Southern California Monte Jade Science and Technology Association, Speaker, March 2011.
  • Crude Oil and Natural Gas Royalties, for Seminar: Agreements and Disputes in Oil and Gas Production, Speaker, October 2010.
  • Natural Gas Anti-Trust Cases: A Perspective from the Participants, Antitrust Section of Los Angeles County Bar, Speaker, January 2007.
  • At Sword's Point Energy Issues in the Interface of Intellectual Property, New Technology and Antitrust, Moderator, June 2008.
  • Western States Lands Commission Meeting, 1999.
  • Interstate Oil and Gas Compact Commission, Royalty-In-Kind Workshop, 1998.
  • California Independent Producers Association, 1998.
  • Mineral Management Services Meeting, 1998.
  • Mineral Management Services Meeting, 1996.
  • National Stripper Well Association, Annual Meeting, 1995.
  • Western and Eastern States Lands Commission Meeting, 1991.


  • Los Angeles County Bar (Member, Sections on Antitrust & Unfair Business Practices, Litigation) (Chair of the Antitrust & Unfair Competition Section 2011-2012, Member 2004 - Present)
  • State Bar of California (Member, Sections on: Antitrust & Unfair Competition, Litigation)
  • Association of Business Trial Lawyers
  • Rocky Mountain Mineral Law Foundation
  • National Association of Royalty Owners (NARO)
  • American Philosophical Association
  • Board of Directors Pasadena Young Musicians Orchestra, Vice President and President, 2001-2014
  • Board of Directors, Pasadena Symphony & Pops, 2015-Present

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