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Gregory J. Casas is Co-Managing Shareholder for the Austin office and focuses his practice on antitrust, complex business litigation, and energy and natural resources law. Greg's antitrust and complex business litigation practices are international in scope. His antitrust practice includes litigating price-fixing, bid-rigging, and market allocation claims, and providing counseling for DOJ/FTC investigations, joint venture formation, use of AI and algorithmic software, ESG initiatives, mergers and acquisitions, pricing plans, and other contractual relationships. Greg's complex business litigation experience includes class action defense, commercial disputes, and international dispute resolution in Latin America, Europe, and Africa. His energy experience includes litigating power plant construction disputes, oil and gas leases and joint operating agreement disputes. Greg has litigated cases in federal and state courts in Texas, California, Illinois, Georgia, Nevada, New York, New Jersey, Tennessee, Puerto Rico and the District of Columbia. He has handled appeals in Texas, Georgia, The Fifth Circuit, the Second Circuit and the District of Columbia .


  • Antitrust
  • Class action defense
  • International
  • Commercial
  • Energy and natural resources



  • Currently representing a multifamily rental housing property manager in an MDL comprised of antitrust cases pending in over 20 states relating to claims that property managers around the country have fixed or artificially increased rental rates through the use of algorithmic pricing software.
  • Currently representing the nation’s largest natural and organic grocery store chain in a class action in the District of Columbia involving non-payment of bonuses. As part of this claim, Greg has argued before the District of Columbia Circuit that the Supreme Court’s recent constitutional ruling in Bristol Myers Squibb Superior Court applies to nationwide class actions.
  • Represents a natural and organic food grocery chain in multiple pending class actions. Cases involve alleged overpricing of pre-packaged foods, improper labeling, wrongful termination claims, securities claims, and ERISA violations. Secured dismissals in cases involving securities litigation and ERISA violations, which have both been affirmed by the Fifth Circuit. Markman v. Whole Foods Market, Inc., 269 F. Supp.3d 779 (W.D. Tex. 2017) aff’d 905 F.3d 892 (5th 2018); Martone v. Robb, 2017 WL 3326966 (W.D. Tex. Aug. 2, 2017) aff’d 902 F.3d 519 (5th Cir. 2018). Recently obtained summary judgment in client’s favor in an alleged over pricing class action, pending in the Southern District of New York. In re Whole Foods Market Group, Inc. Overcharging Litig., 2019 WL 3219690 (S.D.N.Y. July 17, 2019).
  • Represented a reseller of residential-mortgage-backed securities in putative class action filed in Travis County, Texas by state-affiliated investor.
  • Defended a "super-major" oil and gas company in a class action brought in Latin America by all purchasers of retail gasoline against "super-major" oil companies.
  • Currently representing one of the largest food distributors in the Southwestern United States in an antitrust claim in federal court in Illinois. The client alleges that the largest chicken producers in the United States have engaged in a multi-year conspiracy to fix prices and coordinate supply of broiler chickens. This case is part of a larger series of cases involving class actions and multiple district litigation among various direct purchasers.
  • Currently representing a midwestern multiple listing service in an antitrust case in California regarding terms and conditions for listing properties on multiple platforms and listing services. Plaintiff alleges that the multiple listing services across the country have entered into an illegal agreement to limit or prohibit private or pocket listings of residential real estate for sale.
  • Regularly counseling companies regarding the use of AI and other algorithmic software in order to limit antitrust risks that may arise in real estate, manufacturing, and retail industries.
  • Counseling companies with regard to ESG initiatives in relation to allegations that participating in initiatives are alleged violations of state and federal antitrust and competition laws.
  • In the health care area represented the Texas subsidiary of a multi-state payor in an antitrust case alleging an illegal boycott under the Sherman Act. Plaintiffs alleged that the client conspired with other payors to prevent Plaintiffs from providing home treatment options in the allergy testing and treatment market in Texas.
  • Currently representing a company in the market for environmental risk assessment data for property assessments in bringing a claim under Section 2 of the Sherman Act against the market leader. The case involves claims of sham litigation, copyright infringement, improper product bundling, and business disparagement. The case is pending in federal court in the Southern District of New York.
  • Represented Chinese steel manufacturer in ITC proceeding alleging trade claims and antitrust violations arising from various manufacturers’ export of steel into the United States.
  • Represented an agency of eastern European country in MDL proceedings in Chicago involving antitrust claims related to sale of certain commodities. 
  • Represented an association of physicians in a suit alleging violations of Section 1 of the Sherman Act as well as common law torts such as tortious interference and business disparagement.
  • Counsel health care providers and hospitals about antitrust issues arising out of land-use restrictions, joint venture formation and negotiations with payors.
  • Represented a medical equipment rental company in antitrust action. Claims alleged arose under Sections 1 and 2 of the Sherman Act and Common Law Tort.
  • Represent key entity responsible for negotiating pricing programs and establishing distribution solution under HRSA’s Prime Vendor Program in a suit alleging violations of Section 1 of the Sherman Act, the Robinson-Patman Act, and Common Law Tort.
  • Provided counseling and represented domestic and international clients regarding Hart-Scott-Rodino filings and related Second Requests before the U.S. Department of Justice and Federal Trade Commissions. Industries involved included agriculture and gasoline, natural gas transmission, gasoline and crude oil transmission and refining, health care, hotels, and financial services.
  • Represented retailer in real estate dispute with joint venture partner over distribution of proceeds from sale of land to the U.S. government. The matter involved both state court litigation and AAA arbitration.
  • Represented Houston-based hedge fund in suit arising out of a failed investment in a film finance company. The fund asserted claims for fraud and negligent misrepresentation. 
  • Coordinating Counsel for a national natural and organic foods grocery chain in various disputes in New Jersey, New York, Connecticut, Arizona, Florida, Texas, California and Illinois.
  • Represented Japanese technology company in case in federal court in Houston regarding an alleged infringement of copyrighted and trademarked materials of a U.S. company on products being developed and marketed in Japan.
  • Represented Chinese-based designer and fabricator of semiconductors in claims against competitors related to financing and building a new fabrication plant in China.
  • Currently representing Texas electric co-op in federal court in East Texas in contract dispute with regional supplier related to a right of participation in future development of traditional and renewable generation facilities.
  • Represented Caribbean oil and gas producer in arbitration before the International Chamber of Commerce (ICC) regarding taxes from the purchase of offshore oil and gas leases.
  • Represented West African nation in disputes involving the development and sale of that country’s natural resources in proceeding before the ICC and ICSID, including representation of the country in the first ever Conciliation under ICSID’s Additional Facility Rules.
  • John v. Whole Foods Market Group, Inc., No. 19-2528-cv (2d Cir. Aug. 25, 2020) 
  • Molock v. Whole Foods Market Inc., 317 F. Supp.3d 1 (D.D.C. 2018).
  • Markman v. Whole Foods Market, Inc., 269 F. Supp.3d 779 (W.D. TX 2017) aff’d 905 F.3d 892 (5th Cir. 2018).
  • Martone v. Robb, 2017 WL 3326966 (W.D. Tex. Aug. 2, 2017) aff’d 902 F.3d 519 (5th Cir. 2018).
  • In re Whole Foods Market Group, Inc. Overcharging Litig., 2019 WL 3219690 (S.D.N.Y. July 17, 2019).
  • Academy Allergy & Asthma in Primary Care v. Superior HealthPlan, Inc., 2018 WL 43434441 (W.D. Tex. July 23, 2018).
  • In re Deutsche Bank Securities, Inc., 2014 WL 6045153 (Tex. App.—Austin, Nov. 25, 2014).
  • Beneplace Inc. v. Pitney Bowes, Inc., 2016 WL 11582932 (W.D. Tex. April 29, 2016).
  • Schnake ex. rel. Trincan Oil Ltd. V. Coast to Coast Energy, 2009 WL 2633699 (S.D. Tex. Aug. 23, 2009).

Recognition & Leadership

  • Listed, The Best Lawyers in America, Commercial Litigation, 2024
  • Listed, The Legal 500 United States
    • Dispute Resolution - Corporate Investigations and White-Collar Criminal Defense: Advice to Corporates, 2020-2021
    • Dispute Resolution - Corporate Investigations and White-Collar Criminal Defense: Advice to Individuals, 2020-2021
    • Dispute Resolution - General Commercial Disputers, 2020
  • Listed, Chambers USA Guide, Antitrust, 2012, 2015, 2018-2019, and 2022-2023
    • "Recognized Practitioner," 2016-2019
  • Listed, Lawdragon 500, "Leading Litigators in America," Complex Litigation, inc. Antitrust, Energy, 2022-2023
  • Listed, Super Lawyers magazine, Texas Super Lawyers, 2010-2023
  • Listed, Austin Monthly Magazine, "Top Attorneys in Austin," Antitrust, 2020-2022
  • Rated, AV® Preeminent5.0 out of 5.0

°AV®, AV Preeminent®, Martindale-Hubbell DistinguishedSM and Martindale-Hubbell NotableSM are certification marks used under license in accordance with the Martindale-Hubbell® certification procedures, standards and policies.

  • Board Member, Ballet Austin
  • Former Board Member, U.S./Mexico Bar Association
    • Former U.S. Co-Chair, Energy Committee
  • Member, American Bar Association, Antitrust Section
  • Member, Austin Bar Association
  • Member, District of Columbia Bar
  • Member, State Bar of Texas


  • J.D., with honors, Duke University School of Law, 1993
  • B.A., English and Economics, magna cum laude, Boston University, 1990
  • District of Columbia
  • Texas
  • U.S. Court of Appeals for the District of Columbia Circuit
  • U.S. Court of Appeals for the First Circuit
  • U.S. Court of Appeals for the Second Circuit
  • U.S. Court of Appeals for the Third Circuit
  • U.S. Court of Appeals for the Fifth Circuit
  • U.S. Court of Appeals for the Ninth Circuit
  • U.S. Court of International Trade
  • U.S. District Court for the District of Colorado
  • U.S. District Court for the District of Columbia
  • U.S. District Court for the Eastern District of Texas
  • U.S. District Court for the Northern District of Texas
  • U.S. District Court for the Southern District of Texas
  • U.S. District Court for the Western District of Texas
  • Supreme Court of the United States
  • Spanish, Conversational