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“Mark Arnold sets the gold standard for appellate practice in St. Louis.”

Missouri Supreme Court Justice Richard Teitelman


Mark strives to think outside the box and bring a fresh approach to each case. A litigator for 40 years, Mark is a seasoned debater who is energized by outsmarting his opposition.

Mark puts that competitive nature to work for his clients as he leads them through all phases of complex litigation. His practice focuses on antitrust, securities pension and welfare, toxic tort and product liability matters. He also handles appeals of major cases, interpreting complex federal statutes such as the Employee Retirement Income Security Act (ERISA) and the Racketeer Influenced and Corrupt Organizations Act (RICO).

In addition, Mark has extensive experience defending class actions.

“Mark Arnold sets the gold standard for appellate practice in St. Louis.”

Missouri Supreme Court Justice Richard Teitelman




  • The Best Lawyers in America, Appellate Practice, Commercial Litigation, 2001-2019
  • Best of CLE Spotlight, MoBar CLE, 2013
  • Missouri & Kansas Super Lawyers, Appellate, 2005-2018; Top 100, 2006; Top 50 St. Louis, 2005-2008
  • Missouri Bar Pro Bono Wall of Fame, 2012
  • The Missouri Bar, W. Oliver Rasch Award for Outstanding Article, 1996


  • J.D., Washington University School of Law
    • Order of the Coif
    • Washington University Law Quarterly, editor-in-chief
  • A.B., Oberlin College


  • Missouri
  • U.S. District Court, Northern District of Florida
  • U.S. District Court, Southern District of Illinois
  • U.S. District Court, Eastern District of Missouri
  • U.S. District Court, Western District of Missouri
  • U.S. Court of Appeals, First Circuit
  • U.S. Court of Appeals, Second Circuit
  • U.S. Court of Appeals, Third Circuit
  • U.S. Court of Appeals, Fourth Circuit
  • U.S. Court of Appeals, Fifth Circuit
  • U.S. Court of Appeals, Sixth Circuit
  • U.S. Court of Appeals, Seventh Circuit
  • U.S. Court of Appeals, Eighth Circuit
  • U.S. Court of Appeals, Ninth Circuit
  • U.S. Court of Appeals, Tenth Circuit
  • U.S. Court of Appeals, Eleventh Circuit
  • U.S. Court of Appeals, Federal Circuit
  • U.S. Court of Appeals, District of Columbia Circuit
  • U.S. Supreme Court

Professional Associations and Memberships

  • American Health Lawyers Association
  • American Law Institute, Life Member, 2014-present 
  • The Missouri Bar
  • Missouri Supreme Court, Civil Rules Committee; Ad Hoc Committee on Expert Discovery Rules
Featured Case Study

Lender Prevails in Real Estate Class Action Suit

In a case in the U.S. District Court in Minnesota, Mark successfully defeated class certification for borrowers who alleged that the yield spread premium a lender paid a mortgage loan broker constituted illegal kickbacks and fee splitting under the Real Estate Settlement Practices Act (RESPA). In response to the defendants’ motion for reconsideration, the court reversed its earlier decision granting class certification and also granted the defendants’ motions for summary judgment on the liability issues, dismissing the claims with prejudice.

Additional Experience
  • Obtained outright reversal in Arkansas Court of Appeals of a million-dollar wrongful death judgment against a mall. A disgruntled ex-employee of a mall tenant killed the manager who had fired him. The court held that a landlord owes no duty to an employee of a tenant.
  • Successfully litigated patents and patent licensing for Monsanto seed and other agricultural products.
  • Represented Farm Credit entities, including AgriBank, its predecessors and various production-credit associations, on general litigation matters.
  • Counseled lenders and buyers of farm products on enforceability of liens on agricultural products.
  • Obtained favorable ruling from Eighth Circuit Court of Appeals that affirmed lower court order denying remand and class certification in Class Action Fairness Act (CAFA) lawsuit against Chicago Title Insurance Co.
  • Defeated class certification in major consumer fraud case against national postsecondary education provider in Madison County, Illinois. Client was accused of violating Illinois Consumer Fraud Act and Private Business and Vocational Schools Act by not providing accurate information to prospective students for seven years. Plaintiffs' demand to settle case was more than $20 million. State appeals court denied class certification.
Outside the Office

Mark is an avid Major League Baseball fan. He takes in as many St. Louis Cardinals games as he can.