Regina Loureiro


Regina advises clients on a range of antitrust and competition issues, regularly representing them before the U.S. Department of Justice (DOJ) and U.S. Federal Trade Commission (FTC). Her practice focuses on merger clearances, agency investigations and civil litigations.

Regina represents clients in all aspects of the merger review process, including merger clearances before the FTC and DOJ and compliance with the Hart-Scott-Rodino Antitrust Improvements Act of 1976 (HSR Act). She also advises on global merger notification requirements and coordinates antitrust approval efforts in jurisdictions throughout the world. Regina has represented a pharmaceutical and laboratory equipment client before the FTC in a milestone prior approval petition, the first of its kind since a new FTC policy on prior approvals in consent decrees. She has also represented clients in merger challenges in federal court. Her experience spans dozens of industries including technology, pharmaceuticals, transportation, consumer goods manufacturing and chemicals.

During law school, she was the Senior Forum Editor of the American University Law Review.


Pro bono

Representing veterans before the Board of Veterans Appeals relating to benefits.

Representing individual in U.S. immigration and federal court relating to unconstitutional sentencing and deportation.

Published Work

  • Regina Loureiro, Noah Brumfield, Michael Gallagher, Allain Andry, Mark Gidley, Kathryn Mims, 2020, The US DoJ and State Attorney-General propose federal additions to the Price Gouging Framework following the COVID-19 pandemic, Article in e-Magazine, March 2020, e-Competitions Concurrences



Admitted: Bar of the District of Columbia, 2019


J.D, American University Washington College of Law, 2019 B.S., International Affairs, Florida State University, 2015
A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.