Antitrust lawyers

Marc A. Goldman

Partner

Massey & Gail LLP

Marc E. Kasowitz

Partner

Kasowitz LLP

Marc E. Miller

Partner

DLA Piper LLP (US)

Marc Waha

Marc Waha leads our Asia Antitrust and Competition Team. He is based in the Hong Kong and Tokyo offices. Marc advises international companies on antitrust regimes in East Asia, and Asian companies on global competition compliance issues, multi-jurisdictional merger filings and international cartel investigations, particularly in Europe and Asia. For more than 20 years he has represented clients active in a wide variety of industrial and services sectors, with a focus on advising Asian companies on global antitrust and competition law matters.

Norton Rose Fulbright

Marcelo Calliari

Partner

TozziniFreire

Marcelo Gerardo Vaca Guzmán Aparicio

Managing Partner

Vaca Guzmán Siles Sociedad Civil

Marcelo L. Vaca Guzmán

Partner at Vaca Guzmán Siles Abogados, specialising in Antitrust and Corporate Law.

Vaca Guzmán Siles Sociedad Civil

Marcio Soares

Partner

Mattos Filho

Marco Antonio Tena López

Mid Level Associate

Vega, Guerrero & Asociados

Marco Giustiniani

Partner Head of the Administrative and Environmental Departments, Marco works mainly out of our Rome and Milan offices. Since 2021, he has also been a member of the Firm’s Board of Directors. He advises domestic and international clients, both public and private, on a broad range of administrative law issues. In particular, he focuses on public tenders and contracts, both the public transport and public services sectors, electronic communications and the other regulated sectors, antitrust, Pharmaceutical law and Town Planning and Building law. He has also gained a meaningful experience as a litigator before the Council of State and the Administrative Regional Courts since the beginning of his career.

Pavia e Ansaldo

Marcos Payssé

Marcos Payssé, lawyer, mainly works in Banking, Corporate and M&A Department. Partner at Guyer & Regules.

Guyer & Regules

Margaret Segall

Maggie Segall is a member of Cravath's Antitrust Practice. Her practice focuses on transactional matters, antitrust regulatory approval, and government investigations, including civil conduct investigations brought by both federal and state antitrust authorities, as well as general antitrust counseling and critical antitrust litigation. Named “Dealmaker of the Year” by Global Competition Review (GCR) in 2025, Ms. Segall is described as “truly one of the finest antitrust attorneys” and “prolific in securing clearances for high-value mergers, as well as advising clients on government investigations.” (The Legal 500 US) Her clients cover diverse industries, including aerospace and aviation, pharmaceuticals, life sciences, consumer products, media, manufacturing and technology.

Cravath, Swaine & Moore LLP

Margaret Warner

Margaret Warner has served as first chair trial and appellate counsel in state and federal courts in over 30 jurisdictions. Her work has spanned antitrust, commercial, class action, environmental, healthcare, insurance, mass tort, product liability and reinsurance disputes. Margaret has taken numerous cases to verdict/judgment before juries, judges and arbitration tribunals. Many of her cases have involved high-profile public policy issues from the Agent Orange litigation in the 1980s, environmental and Superfund litigation involving such notorious sites as Love Canal and the Hudson River in the 1990s, to sexual abuse, 9/11, antitrust, healthcare, ERISA and COVID-19 litigation in the 21st Century. Please visit McDermott website for full biography: https://www.mwe.com/people/warner-margaret-h/

McDermott Will & Schulte

Margret Caruso

Quinn Emanuel Urquhart & Sullivan, LLP

Marguerite Sullivan

Maggy Sullivan, a nationally recognized trial lawyer, represents multinational clients in complex antitrust litigation and investigations before federal regulators. She ranks among an elite few antitrust trial lawyers who have secured multiple merger litigation victories against the government. Maggy brings strategic foresight and more than two decades of experience to her work managing litigation in all its forms, including: Investigations Complex civil actions Multi-district actions Class actions She regularly develops compelling theories and strategies and excels at persuading parties across the litigation spectrum to adopt her perspective. Maggy has won two of the most complex, high-profile matters in the history of the US Department of Justice (DOJ): the Illumina/GRAIL merger and the Booz Allen Hamilton/EverWatch merger. Her established track record demonstrates excellence in handling sprawling, long-running antitrust matters that run the gamut from investigation, to criminal prosecution, to multi-district litigation, or commercial class actions.

Latham & Watkins

Maria Raptis

Maria Raptis is an antitrust and competition partner in the New York office of Kirkland & Ellis LLP. Her practice focuses on advising clients in connection with antitrust aspects of mergers, acquisitions, litigation, investigations and counseling. She represents clients across a wide range of industries, including healthcare and pharmaceuticals, technology, consumer products, financial services, entertainment and manufacturing. She also has substantial experience litigating antitrust cases. Prior to joining Kirkland, her recent matters included defending Activision Blizzard in its acquisition by Microsoft, and Juniper Networks in Hewlett Packard Enterprise’s acquisition of the company.

Kirkland & Ellis LLP

Mariana Carrión

Counsel of the Life Sciences practice of Assembla, with additional capabilities on Administrative and Antitrust Law. She has more than 15 years of experience providing legal advice and representation to international and local companies in a wide range of industries.

Assembla

Marina Androulakakis

Partner Marina is an expert in EU, competition and antitrust law. She joined the Firm in 1997 and advises national and international clients on antitrust, merger control and State aid issues, with substantial experience in cross-border and cross-section transactions, risk and strategy assessment and regulatory compliance. Her work includes FSR and FDI screening advice. Marina has extensive experience in successfully representing clients across various industries in alleged cartel and abuse of dominance cases before the Hellenic Competition Commission. She also has considerable expertise in merger cases and has effectively coordinated multi-jurisdictional filings and obtained clearance for high-profile M&A transactions from the Hellenic Competition Commission and the European Commission in a wide range of industry specialisations. Marina has an expertise in assessing commercial agreements and policies for their compliance with competition law and also provides on-site assistance and practical guidance in dealing with dawn raids. Marina has significant experience in advising clients on emerging and existing data protection requirements, including identifying gaps and areas of potential infringement of data protection laws, supporting clients on employment related privacy matters and advising on internal investigation procedures and data breach incidents. Marina also supports clients in relation to compliance with international sanctions regimes. Her work includes advising on sanctions monitoring and reporting requirements and the design and implementation of compliance programs, as well as assisting clients to obtain authorization from national authorities and liaising with the regulators.

Bernitsas

Mark Botti

Partner

Baker Botts L.L.P.

Mark Gidley

Partner

White & Case LLP

Mark Goodman

Mark Goodman is a partner in the Firm's San Francisco office who serves as co-chair of the Firm's North America Commercial Litigation group and is part of the North America Trial Team. Mark has led complex multidistrict litigation, handled class actions of numerous kinds and tried cases in state and federal courts across the US for both domestic and international clients. Mark regularly presents on product liability, risk mitigation and cross-border disputes. A Chambers-ranked lawyer, Mark is listed in Who's Who in American Law and a fellow of the American Bar Association. Mark has been regularly recognized as a Northern California Super Lawyer, a member of the Legal 500 and as a member of the International Who's Who of Professionals.

Baker McKenzie

Mark Hamer

Mark H. Hamer is Global Chair of the Firm's Antitrust & Competition Practice Group, comprised of over 250 competition lawyers in 60 offices across 43 countries. Before 2020, he served as its North America Chair. Mark's practice spans across all types of antitrust matters, from high-stakes litigation to strategic merger clearance to bet-the-company criminal and civil investigations. Before joining Baker McKenzie, Mark served as a trial attorney in the Antitrust Division of the US Department of Justice, where he was involved in some of the DOJ's highest-profile antitrust trials.

Baker McKenzie

Mark Herring

Mark Herring is co-leader of Akin’s state attorneys general practice and served for eight years as attorney general of Virginia, during which he led many litigation and appellate teams that won high-profile cases before the U.S. Supreme Court, the U.S. Court of Appeals for the 4th Circuit and other state and federal courts involving issues such as consumer protection, antitrust, health care fraud, constitutional challenges, environmental protection, civil rights and education. He also spearheaded large, complex investigations in the technology, financial services, pharmaceuticals and insurance sectors and led high-profile investigations internal to state agencies and institutions. Mark has substantial experience working closely with state attorney general offices—on both sides of the aisle—across the country and, while in office, further strengthened those connections through his significant efforts with leading national organizations of state attorneys general. Mark is also a member of the adjunct faculty at the University of Virginia School of Law, where he lectures on state attorney general law. To learn more about Mark, please visit his full profile: https://www.akingump.com/en/lawyers-advisors/mark-r-herring

Akin

Mark Lenihan

Associate - Litigation and Investigations

Bryan Cave Leighton Paisner