Marguerite Sullivan

Practice Areas

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.

Ms. Sullivan 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. Ms. Sullivan 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.

Ms. Sullivan is regularly recognized for her work by leading industry publications, including Chambers USA, Global Competition Review, Legal 500, and Benchmark Litigation.