Mary O'Connor | Farrow-Gillespie & Heath LLP | Dallas, TX

Commercial Litigation and Arbitration
Securities Litigation and Regulatory Proceedings
Internal Investigations



Mary L. O’Connor’s practice focuses on representing public companies and their officers and directors in commercial litigation and arbitration, securities litigation, internal investigations, and regulatory investigations and enforcement proceedings.

Ms. O’Connor is a member of the Commercial Panel of the American Arbitration Association and is a FINRA arbitrator.

Mary is currently named to the list of Best Lawyers in Dallas by D Magazine, the list of Best Lawyers in America by US News and World Report, and named several times during her career to the list of Texas Super Lawyers (a Thomson Reuters service) by Texas Monthly Magazine.

Mary L. O'Connor | Farrow-GIllespie & Heath LLP
Farrow-Gillespie Heath Witter LLP | Dallas, TX

Practice Areas

  • Commercial Litigation and Arbitration
  • Securities Litigation and Enforcement
  • Internal Investigations


  • J.D., Stanford Law School, 1983
  • B.A., summa cum laude (political science), Bryn Mawr College, 1979

Experience Overview

Ms. O’Connor’s recent engagements include representing —

  • a landlord in obtaining a 7-figure jury verdict for breach of a commercial lease agreement and successfully defending that verdict on appeal;
  • a supplier of frac sand in a suit for payment on a 7-figure account;
  • an Ohio-based manufacturing company in a Securities and Exchange Commission investigation of fraudulent accounting practices by the vice president for finance of one of its subsidiaries
  • a publicly-traded insurance holding company and its board of directors in derivative litigation arising from the proposed acquisition of the company by a major professional liability insurance company
  • a leading provider of nutritional supplements in a shareholder class action, shareholder derivative and Texas attorney general litigation related to marketing practices of the company’s independent sales associates

Internal Investigation Experience

  • Investigated off-the-books transactions by employees at field locations of publicly-held oil and gas company
  • Investigated whistleblower allegations by an employee of a publicly-held company
  • Investigated potential insider trading issues by employees of publicly-held companies in oil and gas and other industries
  • Investigated related party transactions involving an employee of a publicly-held oil and gas company
  • Investigated anonymous whistleblower allegations involving contract execution, accounting practices, and executive perquisites for a publicly-held software and services company
  • Investigated accounting and internal control issues at multiple locations of a publicly-held manufacturing and services company

Court Admissions

  • U.S. District Court for the Northern District of Texas
  • U.S. District Court for the Southern District of Texas
  • U.S. District Court for the Western District of Texas
  • U.S. Court of Appeals, 5th Circuit
  • U.S. Supreme Court
  • All Texas courts

Publications & Presentations

  • Panelist, “Avoiding and Untangling Knots in Company Internal Investigations,” National Association of Minority & Women-Owned Law Firms, February 2018 Business Meeting
  • Author and Speaker, “Advanced Arbitration: Nuances in Arbitration Law,” presented with Scott T. Williams, Texas Center for the Judiciary, 2013 Civil Justice Conference
  • “Chinks in the Enforcement Armor: Recent Decisions Erode SEC’s Favored Remedies” by Mary L. O’Connor, Patrick G. O’Brien, Bloomberg BNA Securities Regulation and Law Report, November 2012
  • “The Conduct of Independent Investigations – and the General Counsel’s Role,” The Metropolitan Corporate Counsel, April 2007