Mark Boyko, Bailey Glasser Photo

Mark G. Boyko


Mark Boyko practices primarily in the area of complex fiduciary breach and prohibited transaction litigation, representing clients in actions brought under the Employee Retirement Income Security Act of 1974 (ERISA). He has secured judgments and settlements in this area exceeding $500 million and handled successful appeals in federal circuit courts as well as the US Supreme Court.

Mark is a pioneer in ERISA class action litigation, representing workers and retirees in many of the earliest cases in his field. In these matters, Mark represents 401(k) plan participants alleging breach of fiduciary duties in order to hold employers and Wall Street accountable for the plans’ investments and fees.

His practice also includes numerous private company ESOP cases in which he represents workers claiming that fiduciary trustees caused their employee stock ownership plans (ESOPs) to overpay corporate insiders for private company stock. Additionally, Mark represents pension plan participants in cases alleging that plans using decades-old mortality tables have unfairly reduced monthly benefits for married retirees.

Mark also handles matters related to the denial of long-term disability benefits for people impacted by COVID-19, including individuals who are immunocompromised or have other issues that impact their ability to be in-person at workplaces, or who have long-haul COVID.

Mark's practice additionally includes providing legal and strategic services to founders, startups, and small businesses from pre-conception through Series-A funding.

Awards & Accolades

Chambers USA, Nationwide Department Ranking - ERISA Litigation: Mainly Plaintiffs (2023)

Super Lawyers Rising Star, Missouri, Class Action/Mass Torts, Employee Benefits, Business/Corporate, Personal Injury - General (2012-2020)


LL.M., New York University School of Law, 2005

J.D., University of Missouri - School of Law, 2004

B.A., University of Illinois at Urbana–Champaign, 2001


  • Missouri
  • Illinois
  • New York


Representative Matters

  • Representing surgeon in federal case against Unum related to COVID-19 and the denial of long-term disability benefits under an ERISA long-term disability plan.
  • Represents employees and 401(k) plan participants in litigation alleging employers used their own expensive proprietary investment products in the plans because of the benefit to the employer
  • Represents retirees and defined benefit pension plan participants in litigation against employers such as American Airlines and Anheuser Busch concerning the actuarial calculations the plans use to calculate pension benefits
  • Represents current and former employees in litigation alleging that the purchase or sale of privately held stock by an Employee Stock Ownership Plan (ESOP) was not at market prices and instead done to benefit the corporate founders or insiders
  • Represents workers and retirees alleging their employer imprudently concentrated their 401(k) plan investments in single stocks or a small number of stocks
  • Represents Embark Veterinary, Inc., a canine genetic testing company, on corporate matters from company origin
  • Represents startups in diverse fields including medical monitoring and YouTube/entertainment

News & Insights

News & Insights

Community & Professional

Community and Professional Activities

Director, Kirkwood R-VII School District

Director, St. Louis Area Diaper Bank

Director, Friends of Kathy J. Weinman Shelter for Victims of Domestic Violence

Vice-Chair, Employee Benefits General Committee, American Bar Association’s Torts, Trial, and Insurance Practice Section

St. Louis County Economic Rescue Team (2020-2021)

Board Member, Places for People (2009-2021)

Former professional soccer referee

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