M. Sean Royall

• Graco Inc. v. Carlisle Construction Materials, LLC (D.Del.): Lead trial counsel for plaintiff/counter-defendant Graco; obtained winning jury trial victory in defense of fraud and antitrust monopolization claims asserted by defendant Carlisle.
• Tundra Inc. v. Faire Wholesale, Inc. (N.D. Cal. & 9th Cir.): Lead counsel for Tundra in this still-ongoing monopolization suit based on allegations of unlawful exclusive dealing, and in the related Ninth Circuit appeal.
• Perez v. Fairfax County Public Schools, et al. (E.D. Va. & 4th Cir.): Lead counsel to defendant school division and individual administrators; obtained complete dismissal of all claims before district court and now defending that outcome in related Fourth Circuit appeal.
• Innovative Health, LLC v. Biosense Webster, Inc. (9th Cir.): Co-lead counsel in this ongoing antitrust appeal.
• In re Nexstar-TEGNA Merger Litigation (E.D. Cal.): Counsel to plaintiff DIRECTV in this ongoing antitrust challenge to the Nexstar-TEGNA merger.
• Dorrell v. Constellation Energy Corp, et al. (D. Md.): Counsel to defendant The Southern Company in this pending putative antitrust class action.
• In re Namenda Indirect Purchaser Antitrust Litigation (S.D.N.Y.) – Represented Forest Labs. and affiliates in this still-ongoing indirect purchaser antitrust class action involving allegations of “product hopping” and a challenged “reverse payment” patent settlement.
• In re Restasis Antitrust Litigation (E.D.N.Y.) – Served as lead counsel for Allergan in this consolidated MDL antitrust class action involving complex patent- and FDA-related monopolization claims predicated on allegations of delayed entry of generic drugs. Cases settled favorably for defendants after class certification and summary judgment briefing and arguments.
• U.S. ex rel. Silbersher v. Allergan (N.D. Cal.) – Served as lead counsel for Allergan in this False Claims Act litigation in which a private relator sought to assert claims of alleged fraud against the government predicated on a patent-related theory and assertions of delayed generic drug entry.
• In re JUUL Labs., Inc. Antitrust Litigation (N.D. Cal.) – Served as lead antitrust counsel in this still-ongoing consolidated MDL antitrust class action challenging an allegedly unlawful agreement.
• U.S. v. AT&T (C.D. Cal.) – Served as lead antitrust counsel for AT&T in this suit in which DOJ asserted that AT&T’s DirecTV unit engaged in improper coordination and information sharing relating to pay TV distributors’ negotiations with the provider of sports-related television content; case settled on highly favorable terms after full briefing of AT&T’s motion to dismiss.
• FTC v. Lending Club (N.D. Cal.) – Served as lead counsel for Lending Club in this suit in which the FTC asserted multiple consumer protection-based claims relating to Lending Club’s marketing and advertising practices and privacy-related compliance; argued summary and obtained partial victories; case settled favorably.
• U.S. v. AT&T (D.D.C. & D.C. Cir.) – Played an important role on the trial team in this landmark case in which AT&T defeated a DOJ antitrust challenge to the company’s US$85 billion acquisition of Time Warner, an outcome that was later affirmed on appeal in the D.C. Circuit.
• SureShot v. Topgolf (S.D. Tex. & 5th Cir.) – Served as lead counsel for Topgolf in this antitrust suit asserting monopolization claims; obtained full dismissal of all claims by district court and unanimous affirmance.
• Cipla v. Amgen (D. Del. & 3d Cir.) – Served as lead counsel for Amgen in this monopolization suit brought by a generic drug competitor; argued preliminary injunction motion and participated in later interlocutory appeal.
• Shire v. Allergan (D. N.J.) – Served as lead counsel for Allergan in this competitor monopolization suit involving alleged bundling and exclusive dealing practices; argued successful motion to dismiss.
• Hartig v. Allergan (D. Del. & 3d Cir.) – Served as lead counsel for Allergan in this putative antitrust class action asserting that Allergan delayed generic entry through alleged “product hopping”; argued successful motion to dismiss and later defended that ruling through oral argument before the Third Circuit; case was settled on highly favorable terms after remand to district court.
• Apotex v. Allergan (D. Del.) – Served as lead counsel for Allergan in this competitor monopolization suit predicated on claims of unlawful “product hopping”; obtained highly favorable settlement after the close of fact and expert discovery.
• Amphastar v. Sanofi-Aventis (C.D. Cal.) – Served as lead counsel for Sanofi in this competitor monopolization suit asserting patent- and FDA-related antitrust claims; successfully argued for dismissal of all claims.
• U.S. ex rel. Amphastar v. Sanofi-Aventis (C.D. Cal & 9th Cir.) – Served as lead counsel for Sanofi in this suit in which a competing generic drug company, having had its own antitrust claims dismissed, sought to assert related False Claims Act claims as a purported relator; case was fully dismissed by the district court and the outcome was affirmed by the Ninth Circuit.
• FTC v. Commerce Planet (9th Cir.) – Represented former Commerce Planet CEO in this FTC consumer protection suit in which the client, represented by prior counsel, was subjected to a judgment with significant personal liability.
• Stanwood v. Mary Kay Cosmetics (C.D. Cal.) – Served as lead counsel for Mary Kay in this putative class action case alleging fraud and unfair competition relating to the company’s prior participation in industry pledge not to conduct animal-based testing; obtained full dismissal of all claims.
• Avery Dennison v. 3M Corp. (D. Minn.) – Served as lead antitrust counsel for 3M in this competitor suit alleging that 3M monopolized markets through wrongful patent-related conduct in the context of industry standard-setting activities; case settled on highly favorable terms following the close of fact and expert discovery.
• In re Wellbutrin XL Antitrust Litigation (E.D. Pa.) – Served as lead counsel for Biovail in this antitrust class action alleging patent-related monopolization and conspiracy claims.
• Todd v. Exxon, et al. (S.D.N.Y.) – Served as lead antitrust counsel for Phillips Petroleum in this putative antitrust class action alleging conspiracy claims based on asserted improper sharing of salary and benefits information.
• Neon Systems v. BMC Software (Tex. Civ.) – Served as lead antitrust counsel for BMC Software in this competitor suit alleging that BMC had monopolized markets through unlawful pricing and bundling practices; case settled favorably shortly before trial.
• Atlantic Coast Airlines v. Mesa Airlines (D.D.C.) – Served as trial counsel for Atlantic Coast Airlines in this successful antitrust action obtaining a preliminary injunction barring United Airlines and Mesa Airlines from proceeding with a contemplated business arrangement.
• U.S. v. AMR Corp. (D. Kansas) – Represented American Airlines and parent AMR in this government antitrust suit alleging predatory pricing; case resolved through summary judgment for defendants.*
• Continental Forge v. Sempra Energy (Sup. Ct. Cal.) – Represented Sempra Energy and affiliates in this suit alleging antitrust conspiracy claims.
• Longhorn Partners Pipeline Co. v. Holly Corp. (W.D. Tex.) – Represented Holly Corp. in this antitrust suit alleging monopolization of West Texas petroleum pipelines.
• Litton Systems v. Honeywell (C.D. Cal. & 9th Cir.) – Represented Honeywell in this competitor monopolization suit alleging that Honeywell improperly excluded competition in the market for commercial avionics systems; successfully argued motion for directed verdict on majority of claims at issue.
• Continental Airlines v. American Airlines (S.D. Tex.) –Represented American Airlines in this suit alleging improper predatory pricing relating to American’s introduction of a new fare structure; obtained favorable jury verdict.

Government Investigations

• Kurbo/WW Inc. – Lead counsel for WW International and affiliate Kurbo in connection with FTC privacy (COPPA) investigation and settlement.
• Google/Fitbit – Counsel for Fitbit in connection with DOJ investigation of Google’s successful US$2.1 billion acquisition of Fitbit.
• AT&T/Time Warner – Counsel for AT&T in connection with DOJ investigation of the company’s successful US$85 billion acquisition of Time Warner.
• AT&T/DirecTV – Counsel for AT&T in connection with DOJ investigation of the company’s successful US$48 billion acquisition of DirecTV.
• Facebook – Lead counsel for Facebook in connection with FTC investigation relating to compliance with prior 2012 consent order prescribing certain privacy-related standards and practices; also lead counsel for the company in connection with the prior 2012 FTC privacy investigation.
• Bazaarvoice – Lead counsel for Bazaarvoice relating to DOJ antitrust and order compliance investigations.
• Ticketmaster/LiveNation – Lead counsel for Ticketmaster in connection with DOJ investigation of the company’s US$2.5 billion acquisition of LiveNation.
• Williams Cos. – Lead antitrust counsel for Williams in connection with proposed US$38 billion acquisition by Energy Transfer Equity LP.
• Leon Max/Max Studios – Lead counsel for Max Studios in connection with FTC investigation of asserted violations of prior FTC consent order imposing restrictions on advertising of textile content of retail garments.
• ValueClick – Lead counsel for ValueClick in connection with FTC consumer protection claims involving various privacy and online advertising issues.
• Allergan – Lead counsel for Allergan in connection with FTC investigation of the company’s successful US$3.2 billion acquisition of Inamed Corp.
• Watson Wyatt – Lead counsel for Watson Wyatt in connection with DOJ investigation of the company’s successful US$3.5 billion acquisition of Towers Perrin.
• United Defense – Lead counsel for United Defense in DOJ investigation of BAe’s successful US$4.2 billion acquisition of UDI.
• Ancestry.com – Lead counsel for Ancestry.com in connection with FTC investigation of the company’s successful acquisition of Archive.com.
• Endocare – Lead counsel for Endocare in connection with FTC investigation of proposed merger with Galil Medical.
• DiedrichCoffee – Lead counsel for Diedrich in FTC investigation of successful merger with Green Mountain Coffee Roasters.
• Numerous other representations as lead counsel in non-public government investigations, including many FTC consumer protection matters, where successful results leading to closures of the investigations caused them to remain non-public matters.

Sean Royall serves as the firm’s Global Practice Head for Antitrust and Consumer Protection. He has spent his entire career handling complex litigation matters and government investigations and is among the country’s most experienced and highly regarded antitrust lawyers. He focuses broadly on antitrust and consumer protection litigation, government investigations, and counseling, and is a highly experienced courtroom litigator with a stellar track record for winning high-stakes cases. Sean is equally effective navigating complex government investigations and advising clients on the details of a wide range of strategic antitrust and consumer protection issues.

Sean previously served at the Federal Trade Commission (FTC) as the Deputy Director of the FTC’s Bureau of Competition. His antitrust career, both in government and private practice, has included work on many major mergers and acquisitions, as well as lead roles in complex litigation matters that often intersect with other areas of law, including patent law, various federal regulatory regimes, consumer protection, and privacy. Sean has deep experience representing clients across a range of industries, including biopharma, healthcare, e-commerce, telecom, financial services, energy, transportation, software, and semiconductors. In addition to his work on U.S. antitrust and consumer protection matters, Sean has worked and advised on many similar cases and investigations in Europe and other parts of the world.

While in government, Sean was the lead trial lawyer in the FTC’s landmark monopolization suit against computer chip maker Rambus Inc., a novel case that established new legal standards applicable to patent disclosure within industry standard-setting consortiums. More recently, Sean played an important role on the trial team for AT&T in the company’s victory over the Department of Justice’s antitrust challenge to AT&T’s US$85 billion acquisition of Time Warner. In addition to his trial experience, Sean has successfully argued appeals in courts around the country.

Sean also has a nationally prominent reputation for his work in the consumer protection area, where he has particularly deep experience handling FTC investigations and associated litigation focused on advertising, marketing, privacy, and data security issues. He brings to this area of his practice deep knowledge of applicable law and agency practice, as well as the skills of an accomplished litigator. 

For well more than a decade, Sean has been given a Band 1 ranking by Chambers USA (2007-2025), which has described him as “top of the field,” “a star in the antitrust world both in counseling and litigation,” and an “extremely talented lawyer and exceptional litigator.”

Sean’s other recognitions include being ranked in Chambers Global for Antitrust – USA (2020-2023); endorsed as “Highly Recommended (Texas)” by Global Competition Review (2025); named a “Litigation Star” for Intellectual Property, Competition/Antitrust, Appellate, and Commercial work by Benchmark Litigation (2023). He is named by Lexology as a \"Competition Thought Leader\" (2025);  The Best Lawyers in America as “Antitrust Lawyer of the Year” (2015, 2018); and The Best Lawyers in America as “Litigation: Antitrust Lawyer of the Year” (2019). He has also been named to the “All-Star List” by BTI Services (2017) and deemed a “National Antitrust MVP” by Law360 (2015); a “Mergers and Acquisitions and Antitrust Trailblazer” by National Law Journal (2015); and a “Life Sciences Star” in Antitrust (2022) and Competition and Antitrust (2018–2019) by LMG Life Sciences. For the fourth year in a row, Sean was also named by Lawdragon as one of the \"500 Leading Litigators in America.\"

Publications

Sean has written extensively on a wide range of topics relevant to, among other things, antitrust law and policy, consumer protection, privacy, FTC process and remedies, class action antitrust litigation, pharmaceutical antitrust, and standard setting. Sean previously served as Editorial Chair of the ABA’s Antitrust Law Journal, and as an editor of the ABA’s Antitrust magazine and of the Von Kalinowski treatise on Antitrust Laws and Trade Regulation.

• Author, “Walker Process:  A Modern Assessment of an Antitrust Classic,” ABA Antitrust Magazine, Summer 2025.
• Author, “A Google Breakup Would Serve Progressive Aims and Punish Business,” Bloomberg Law, October 5, 2023.
• Author, “The FTC’s Punctuated Equilibrium,” ABA Antitrust Magazine, September 2023.
• Author, “The FTC’s COPPA Conundrum: Ambiguities in the Rule and a Dearth of Authoritative Guidance Leave the Agency Vulnerable to Legal Challenges” ABA Antitrust Magazine, September 9, 2022.
• Author, “Antitrust and Consumer Protection at Last Converge,” Corporate Counsel, April 27, 2022.
• Quoted in, “CFPB May Fill Enforcement Gap After FTC’s High Court Loss,” Law360, May 6, 2021.
• Quoted in, “By the Numbers: 5 Practices That Could Drive Big Law in 2021,” Bloomberg Law, December 23, 2020.
• Quoted in, “‘Hipster Antitrust’ Comes for Joe Biden,” New York Times, November 13, 2020.
• “A Watershed Moment? What Comes Next for the FTC in the Wake of AMG,” ABA Antitrust Magazine, August 9, 2020.
• “The Intersection of Antitrust and the False Claims Act,” Headnotes, Dallas Bar Association, June 2020.
• “Unpacking the New FTC/DOJ Draft Vertical Merger Guidelines,” WLF Legal Pulse, March 9, 2020.
• “Seventh Circuit Sets Up Potential Supreme Court Review of FTC Monetary Relief Authority,” ABA Antitrust Magazine, December 12, 2019.
• “Next Stop, Supreme Court? Seventh Circuit Goes Its Own Way on FTC’s Authority to Obtain Monetary Relief,” WLF Legal Pulse, September 3, 2019.
• “Taking Stock of FTC Cybersecurity Enforcement After the Equifax Settlement,” WLF Legal Pulse, August 7, 2019.
• “Ninth Circuit Judges Call for En Banc Review of FTC’s Authority to Obtain Monetary Relief,” WLF Legal Pulse, January 15, 2019.
• Co-author, “Lessons from FTC’s Loss in, and Subsequent Abandonment of, DirecTV Advertising Case,” WLF Legal Pulse, October 23, 2018.
• Co-author, “Are Disgorgement’s Days Numbered? Kokesh v. SEC May Foreshadow Curtailment of the FTC’s Authority to Obtain Monetary Relief,” ABA Antitrust Magazine, Spring 2018.
• “Will Kokesh v. FTC Put a Kink in the Federal Trade Commission’s Disgorgement Hose?” WLF Legal Pulse, July 10, 2017.
• “Antitrust Scrutiny of Pharmaceutical Product Hopping,” ABA Antitrust Magazine, Fall 2013.
• “When Mergers Become a Private Matter: An Updated Antitrust Primer,” ABA Antitrust Magazine, Spring 2012.
• “Evaluating Mergers Between Potential Competitors Under the New Horizontal Merger Guidelines,” ABA Antitrust Magazine, Fall 2010.
• “The Complexities of Litigating Generic Drug Exclusion Claims in the Antitrust Class Action Context,” ABA Antitrust Magazine, Spring 2010.
• “Change?: Merger Enforcement in the New Administration,” The Advocate, Summer 2009.
• “Deterring ‘Patent Ambush’ in Standard Setting: Lessons from Rambus and Qualcomm,” ABA Antitrust Magazine, Summer 2009.
• “The FTC’s N-Data Consent Order: A Missed Opportunity to Clarify Antitrust in Standard Setting,” ABA Antitrust Magazine, Summer 2008.
• “Avoiding the Scarlet ‘S’: The Modern Challenges of Document Preservation and Destruction,” The American Lawyer, June 2005.
• “The Art of Destruction,” The American Lawyer, September 2004.
• “Standard Setting and Exclusionary Conduct: The Role of Antitrust in Policing Unullateral Abuses of a Standard-Setting Process,” Antitrust, 2004.
• “Administrative Litigation at the FTC: Past, Present, and Future,” Antitrust Law Journal, 2003.
• “Noerr Immunity for Sponsoring Litigation: From Burlington Northern to Baltimore Scrap,” Antitrust, 2001.
• “Coping with the Antitrust Risks of Technological Integration,” Antitrust Law Journal, 2000.
• “Disaggregation of Antitrust Damages,” Antitrust Law Journal, 1997.
• “Post-Chicago Economics,” Antitrust Law Journal, 1995.