Jason C. Semmes

JASON SEMMES focuses his practice on representing a variety of companies in merger clearance proceedings and other investigations conducted by the U.S. Department of Justice Antitrust Division and Federal Trade Commission. He frequently counsels clients on critical antitrust risks related to business initiatives such as joint ventures, pricing and distribution strategies, information and data exchange, and trade association collaboration efforts.

Jason is recommended by the Legal 500 United States for Antitrust (2025), where he is lauded in a client testimonial for his “excellent work” on a recent, large transaction. Best Lawyers: Ones to Watch® in America recognized for his work in Antitrust in its 2026 edition.

Jason received his J.D. from the University of Notre Dame Law School and his undergraduate degree from Miami University. At Miami, Jason was a member of the Redhawk football team.

Prior to joining Sidley, Jason was an associate at another international law firm where he focused on defending proposed and consummated mergers before U.S. and international enforcement agencies.

• Lumen Technologies as antitrust counsel in connection with its US$5.75 billion sale of its mass markets fiber-to-the-home business in 11 states to AT&T.
• Kinder Morgan in its US$1.8 billion acquisition of NextEra Energy Partners’ South Texas assets (STX Midstream).
• Nordstrom, Inc. in its acquisition by the Nordstrom family and El Puerto de Liverpool, S.A.B. de C.V. for US$6.25 billion.
• Symplr, a provider of enterprise healthcare operations software, in its acquisition of IntelliCentrics.
• Roundtable Healthcare Partners in the sale of its portfolio company, TIDI Products, to TJC, L.P.
• Stryker Corporation, a global leader in medical technologies, in multiple acquisitions.
  
  

• American Bar Association, Antitrust and Consumer Law Community