Marguerite O'Brien

Marguerite A. O'Brien

New York

Marguerite “Reity” O’Brien focuses on regulatory matters and civil litigation within the firm’s Litigation Department. She has significant experience representing clients in white collar criminal and regulatory investigations and enforcement actions by the DOJ, SEC, PCAOB, and state regulators, including matters relating to auditor independence as well as ESG regulation. Reity also has experience in a broad array of commercial, corporate governance, and bankruptcy litigations in both state and federal courts. Before joining Ballard Spahr, Reity was an associate at a large international law firm.

Prior to her legal career, Reity was a reporter at The Center for Public Integrity, where she covered judicial ethics, lobbying, and federal and state campaign finance.

Professional Highlights

Recognition & Accomplishments

American Judges Association Gavel Award for Distinguished National Reporting on the Judiciary, 2015



Vanderbilt University Law School (J.D. 2018)
Vanderbilt Journal of Entertainment & Technology Law

University of Delaware (B.A., cum laude, 2012)


New York

U.S. District Court for the Southern District of New York

U.S. District Court for the Eastern District of New York