Patrick T. O’Brien

George Sepsakos is a top attorney recognized by Best Lawyers in the practice area(s) of Employee Benefits (ERISA) Law. George, who practices law in Washington, District of Columbia, has been recognized since 2024. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which George is held by other top lawyers in the same geographic and legal practice area.

Eric Frechtel practices in the area of construction and government contracts. He represents general contractors, subcontractors, sureties, and owners, in both the prosecution and defense of claims on large public and private construction projects. He has significant litigation experience before both state and federal courts, including both bench trials and jury trials, and he has considerable experience in construction arbitration as well. Eric’s practice also includes substantial work ...

Nicholas D. SanFilippo serves as a first chair trial lawyer representing employers in actions involving restrictive covenants, employment contracts, the Uniform Trade Secrets Act, and tort claims, including defamation, conversion, wrongful discharge, conspiracy, and tortious interference. He advises management on employment issues related to termination, hiring, reduction in force, restrictive covenants, employment agreements, discipline, and handbooks. Nick represents closely-held businesses...

Brian D. Israel is a top attorney recognized by Best Lawyers in the practice area(s) of Environmental Law and Litigation - Environmental. Brian D., who practices law in Washington, District of Columbia, has been recognized since 2020. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Brian D. is held by other top lawyers in the same geographic and legal practice area.

Began the practice of law at the Federal Power Commission in 1974. Joined Sidley & Austin (now Sidley Austin LLP) in 1977, elected to partnership in 1981. Co-head of Energy practice, 2006- present

J. Mark Poerio is a top attorney recognized by Best Lawyers in the practice area(s) of Employee Benefits (ERISA) Law. J. Mark, who practices law in Washington, District of Columbia, has been recognized since 2013. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which J. Mark is held by other top lawyers in the same geographic and legal practice area.

Alexandra Field is a top attorney recognized by Best Lawyers in the practice area(s) of Communications Law. Alexandra, who practices law in Washington, District of Columbia, has been recognized since 2025. This recognition is based on an exhaustive peer-review survey, reflecting the high esteem in which Alexandra is held by other top lawyers in the same geographic and legal practice area.

Louis Mazawey brings decades of experience as an authority on the tax aspects of employee benefits in all forms to his work at Groom. As counsel to major insurance companies and a variety of plan sponsors—including corporate employers, trade associations, and public retirement systems—Lou has worked closely with qualified plans, 403(b) and 457 plans, IRAs, employee stock ownership plans, executive compensation, retiree medical benefits, plan terminations, mergers and spinoffs, the...

Vincenzo is one of the four founding partners of Rock Creek Energy Group. Vincenzo represents generation owners and developers, energy traders, private equity firms, financial institutions, and other investors on transactional, regulatory, and compliance matters involving the Federal Energy Regulatory Commission (FERC) and advises clients on the requirements of the Federal Power Act, the Public Utility Holding Company Act of 2005, and the Public Utility Regulatory Policies Act of 1978. ‍ ...

Robert P. Trout has over 40 years' experience in civil and criminal litigation. His practice has concentrated primarily on complex commercial litigation and white-collar criminal defense, as well as the defense of administrative agency enforcement actions. He began his legal career at the Department of Justice, where he served for two years in the Criminal Division, followed by four years as an Assistant United States Attorney in Baltimore, Maryland. Mr. Trout served as Associate Deputy Indep...