Katherine Clemons represents clients in a wide variety of antitrust matters. Her practice includes antitrust compliance counseling and assisting clients with government reviews of mergers and acquisitions, filing obligations under the Hart-Scott-Rodino Act, civil and criminal government investigations, and complex civil antitrust litigation.

Ms. Clemons maintains an active pro bono practice, including representation of a death row inmate with strong actual innocence claims in state and federal habeas proceedings, representation of class plaintiffs in civil rights litigation under Title VII, and representation of a U-Visa holder in adjustment of status proceedings before US Citizenship & Immigration Services.

Prior to joining the firm, she served as a law clerk to the Honorable S. James Otero of the United States District Court for the Central District of California in Los Angeles.

Ms. Clemons graduated magna cum laude from Washington University Law School, where she was a member of the Washington University Law Review and the school's award-winning National Moot Court Team. Upon graduation, she was elected to Order of the Coif and awarded the Judge Amandus Brackman Moot Court Prize for written and oral advocacy. Prior to law school, Ms. Clemons earned a bachelor's degree in Theatre & Film from the University of Kansas.


  • Bayer in federal litigation alleging claims of monopolization, tying, and exclusive dealing involving companion animal flea and tick products.
  • GN Netcom as plaintiff in remand after appeal of litigation against major competitor alleging attempted monopolization and exclusive dealing by means of distribution agreements. Resolved by agreement just prior to retrial. GN Netcom v. Plantronics (D. Del.)
  • Major international corporation in criminal antitrust investigation of alleged agreements not to compete for employees.
  • Online retailer in criminal investigation into alleged price fixing.
  • The National Titanium Dioxide Company Limited (d/b/a Cristal) in the sale of its titanium dioxide business to Tronox Limited (est. $2.4 billion), including the FTC's litigation challenging the transaction both in federal court and in FTC administrative proceedings.
  • Monsanto in connection with its $66 billion acquisition by Bayer, which closed after a 20-month DOJ investigation leading to what the DOJ characterized as the "the largest negotiated merger divestiture ever required by the United States." The transaction was reviewed and approved by antitrust enforcers in the US, the EU, and almost 30 other jurisdictions.
  • Global automotive parts manufacturer in DOJ antitrust investigation into alleged price fixing and bid rigging in the automotive parts industry.
  • Fujikura Ltd. and Fujikura Automotive America LLC in ongoing complex multi-district antitrust litigation alleging bid rigging and price fixing of automotive wire harnesses and other products arising out of the government's investigation into the auto parts industry.In re Automotive Parts Antitrust Litigation.
  • Global pharmaceutical manufacturer in DOJ antitrust investigation into pharmaceutical pricing.
  • BP plc in the $2.4 billion sale of its Carson, California refinery and related logistics and marketing assets to Tesoro Corporation.
  • Monsanto in relation to its $930 million acquisition of The Climate Corporation.
  • Fortune 50 company in connection with due diligence in preparation for addressing potential antitrust liability post-merger.
  • Competing global consulting companies in securing unconditional FTC clearance for their combination while avoiding a second request.


Deskbook on Internal Investigations, Corporate Compliance and White Collar Issues (2nd Edition)
PLI Practising Law Institute
Getting the Deal Done in the Age of Big Data Requests - Part 2 (pdf)
The Antitrust Counselor, ABA Section of Antitrust Law, Vol. 13.4
Getting the Deal Done in the Age of Big Data Requests - Part 1 (pdf)
The Antitrust Counselor, ABA Section of Antitrust Law, Vol. 13.3


Washington, DC Super Lawyers
"Rising Star"–Antitrust Litigation, Criminal Defense: White Collar (2016-2021)
Best Lawyers
"Ones to Watch"–Antitrust Law (2021)


  • JD, Washington University School of Law, 2011, magna cum laude, Order of the Coif
  • BGS, University of Kansas, 2006
  • District of Columbia
  • Missouri
  • US District Court, Central District of California, The Honorable S. James Otero

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