Phil Louis, a partner in Armstrong Teasdale’s Corporate Services practice group, primarily focuses on mergers and acquisitions, antitrust and financing matters and also the relationship among owners of businesses. Phil’s past roles as a litigator, tax attorney, vice chair of the firm’s banking department and practicing CPA in tax and auditing provide him with a wide range of experience. This background enhances his corporate practice and benefits the clients he advises and represents.

In the case of Phil’s mergers and acquisitions practice, he primarily represents acquirers but also has extensive experience on the divestiture side of transactions. The matters Phil handles involve stock purchases and sales, asset acquisitions and sales, mergers, consolidations and joint ventures. This area of Phil’s practice includes handling antitrust premerger notifications to the Federal Trade Commission and the Department of Justice as required by the Hart–Scott–Rodino Antitrust Act. Many of Phil’s clients are from the correctional, consumer products and services, lodging and manufacturing industries.

Phil’s practice also involves a wide range of antitrust counseling. In addition to premerger notifications, Phil advises clients about a variety of antitrust issues, including discriminatory, predatory, resale and other pricing issues, exclusivity arrangements and collaborations. Phil has also coordinated global antitrust matters on behalf of clients with the help of a network of outstanding law firms associated with Armstrong Teasdale.

With regard to Phil’s financing practice, he is involved in representing primarily clients seeking funding through a wide array of transactions including traditional credit facilities but also sale and leaseback transactions and equity financings.

Phil has handled a wide range of matters involving the owners of businesses.  This area of practice includes the negotiation and development of contractual arrangements among owners and resolving owner disputes.


  • Saint Louis University School of Law  (J.D., 1983)
  • University of Missouri  (B.S., 1977)


  • New York
  • Illinois
  • Missouri

Professional Activities

  • New York State Bar
  • Illinois State Bar 
  • The Missouri Bar

Charitable and Civic Involvement

  • St. Louis Trust Company (Member, Board of Directors)
  • The Little Bit Foundation (Past Board Member and President)
  • Lydia's House (Past Board Member and President)
  • Sherwood Forest Camp (Past Board Member and President) 
  • St. Louis Urban Debate League (Board Member and Treasurer)
  • 2016 U.S. Senior Amateur Championship (Executive Committee) 
  • 2009 U.S. Women's Amateur Championship (Executive Committee)


  • Missouri/Kansas Super Lawyer® Super Lawyers® Business Edition (2005, 2009-present)
  • AV® Peer Review Rated, Martindale-Hubbell


Before entering law school in 1980, Phil practiced as a certified public accountant in auditing and tax. Upon graduation from law school in 1983, he commenced employment as a law clerk at the Missouri Court of Appeals, Eastern District. In 1984, he joined the law firm of Shepherd, Sandberg and Phoenix (now Sandberg, Phoenix and von Gontard), a defense litigation firm, where he primarily handled commercial, products liability and medical malpractice litigation matters.

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