Katherine Clemons is a counsel in the firm’s Antitrust and Competition Practice Group. She is a seasoned antitrust attorney with a proven record of handling complex investigations, mergers, and litigation over nearly 15 years in practice.  

Most recently, as a trial attorney at the Antitrust Division of the U.S. Department of Justice (DOJ), Katherine was a core member of the DOJ’s litigation team leadership and trial team in U.S. v. Google, LLC (Ad Tech), lead attorney for the United States in Nosalek v. MLS Property Information Network, and a key participant in U.S. v. Keysight Technologies, Inc., the Division’s challenge to and proposed settlement of the $1.5 billion merger of Keysight and its competitor Spirent Communications plc. Katherine also led significant nonpublic civil conduct and merger investigations in the professional services, telecommunications, and media industries, and supported similar investigations in other sectors. She also managed investigation teams, coordinated with state attorneys general and international competition enforcers, served as a member of the Division’s E-Discovery Working Group, and developed strategic plans for investigation and litigation.

Katherine brings deep experience navigating the complexities of merger investigations, having led multiple inquiries—including Second Requests—during her tenure at the DOJ. While at the Antitrust Division, Katherine received three Assistant Attorney General’s Awards for her service in merger and litigation work, including for excellence in writing.

Before her career in government service, Katherine was a senior antitrust associate in the Washington DC office of an international law firm, where she represented clients in civil and criminal matters before the Federal Trade Commission, DOJ, and state attorneys general, as well as in private state and federal antitrust litigation in jurisdictions throughout the United States. She acted as lead associate in numerous high-stakes merger, criminal, and litigation matters across a broad range of industries, including cartel investigations for auto parts, agriculture, technology, telecommunications, and healthcare clients.

Having held a leadership role in the American Bar Association’s Antitrust Section since 2019, and currently serving as Vice Chair of the Section’s Books & Treatises Committee, Katherine is actively engaged with the latest policy and legal developments in antitrust law. Katherine clerked for the Honorable S. James Otero of the U.S. District Court for the Central District of California. She earned her J.D. from Washington University School of Law, where she served as senior editor for the Washington University Law Review, and her undergraduate degree from the University of Kansas.