Karen Kazmerzak is a Partner in the Firm’s Washington, D.C. office. A former lawyer within the Federal Trade Commission (FTC), Karen has extensive experience advising clients on antitrust concerns in connection with complex transactions, including obtaining merger clearance in the United States and developing strategies to advocate for antitrust approval in international jurisdictions.
Recognized as a leader in the field by Chambers USA (2018-2024), Legal 500 and a “Litigation Star” by Euromoney’s Benchmark Litigation (2023-2024), Karen is lauded by clients for providing “practical-minded guidance.” She is also recognized for her work representing third-party market participants in connection with opposition to acquisitions and in connection with government subpoenas. Beyond her work for clients on merger clearance matters, she also advises on antitrust matters involving licensing, distribution, pricing and competitor collaborations.
Karen’s extensive private sector and government experience has spanned numerous sectors, including several regulated industries, such as life sciences, energy, transportation, healthcare and telecom, among many others.
Karen’s recent representative matters since joining Simpson Thacher include:
- Bright Health in the sale of Brand New Day and Central Health Plan to Molina Healthcare
- Medline Industries in its $950 million acquisition of Ecolab’s global surgical solutions business
- Funds managed by Charlesbank Capital Partners in connection with their majority growth investment in Petra Funds Group
Prior to joining Simpson Thacher, Karen was co-leader of the global Antitrust/Competition practice at another international firm. She served as an attorney with the FTC from 2006 to 2010.
Karen is an established thought leader on antitrust topics and is an active member of the American Bar Association’s Antitrust Section. She currently serves as an associate editor of Antitrust and previously served as a vice chair of the Transportation and Energy Industries Committee (2012–2018). Karen also co-founded the Women’s Antitrust Forum, a Washington, D.C.-based organization that is focused on bringing together and creating development opportunities for women practicing antitrust law, policy and economics. She also serves as Secretary on the Board of Network for Victim Recovery of DC (NVRDC), a community-based nonprofit that provides free, comprehensive advocacy, case management and legal services to crime victims.
Karen received her J.D. from the University of Iowa College of Law and her B.S. in Microbiology from the University of Iowa. She is admitted to practice in the District of Columbia and New York.
Updated Oct 2024
