Gabrielle G. Hirz


  • JD, cum laude, Boston University School of Law, 2007
  • BA (Political Science), Phi Beta Kappa, General and Departmental Honors, 2004


  • New York, 2017
  • Massachusetts, 2016
  • Pennsylvania, 2016
  • District of Columbia, 2008

Court Admissions

  • U.S. Tax Court
  • U.S. Court of Federal Claims
  • U.S. District Court for the District of Massachusetts
  • Boston Co-Chair, Federal Bar Association Tax Section, 2017-2018
  • American Bar Association

Gabrielle G. Hirz


As a former trial attorney in the Tax Division at the U.S. Department of Justice, Gabby has considerable hands-on litigation experience and an in-depth, insider’s understanding of IRS and DOJ practices and priorities. She is particularly suited to assist clients in all stages of high-stakes tax disputes, and in negotiating favorable settlements.

Gabby has handled all aspects of litigation matters, from developing case strategies, managing fact and expert discovery, and taking and defending depositions to arguing dispositive motions and serving as lead trial counsel. She works with clients in all stages of the audit and appeals process, before the U.S. Tax Court, Court of Federal Claims, and Federal Circuit, and in both tax and general litigation in the U.S. District and Bankruptcy Courts, and the U.S. Courts of Appeals. Additionally, prior to her experience at DOJ, she worked in securities enforcement at a major law firm.

Gabby also maintains an active pro bono practice in a variety of areas, including housing and tax matters, and serves as co-chair of the Boston Chapter of the Tax Section of the Federal Bar Association. 


  • As co-counsel, represented the United States in a tax refund suit involving a complex corporate reorganization analyzed under the judicial doctrines of economic substance and substance over form.*
  • Obtained, as first-chair trial counsel, a favorable decision after trial on behalf of the United States finding that the taxpayer was the true owner of property held by a nominee.*
  • Achieved, as first-chair trial counsel, a favorable morning of trial concession on a contested motion to dismiss a bankruptcy case for bad faith filing.*
  • Prevailed, as first-chair trial counsel, in a bench trial of a refund suit regarding deductibility of hobby losses.*
  • Represented a creditor of a real estate investment company regarding efforts to recharacterize its claim in the Fourth Circuit and U.S. Supreme Court.
  • Represented a large hedge fund in an appeal before the Federal Circuit regarding economic substance of a transaction.
  • Represented the Unsecured Creditors’ Committee in an oil and gas bankruptcy in appeals in the Southern District of New York and Second Circuit regarding objections to plan confirmation and related issues. 
  • Represented a portfolio company in IRS examination regarding the deductibility of management fees paid to private equity sponsors.
  • Represented company concerning audit committee review of tax positions.
  • Representing individual in a gift tax audit regarding the valuation of gifted property before the IRS Appeals Office.
  • Representing a foreign complex trust in IRS appeal regarding withholding on U.S.-source income. 
  • Representing media company in tax litigation in the U.S. Bankruptcy Court.
  • Representing company in IRS audit regarding transfer pricing. 

Experience Prior to Joining the Firm*


  • Quoted, “IRS Could Replace Offshore Voluntary Disclosure Program,” Law360 (April 10, 2018)
  • Brian Studniberg, Gabrielle Hirz and Loretta Richard, “Is Fishing in Tax Waters Getting Easier or Just More High-Tech?” Tax Notes (March 26, 2018)
  • Kat Gregor, Gabrielle Hirz and Isabelle Farrar, “How IRS Is Targeting Offshore Accounts, Virtual Currency,” Law360 (January 23, 2018)
  • Kat Gregor and Gabrielle Hirz, “Staying on Issue: The Internal Revenue Service’s New Issue-Based Audits,” Risk & Compliance (July-September 2017)
  • Gabrielle Hirz, Kat Gregor and Stefan Herlitz, “Remaining Silent Before the Tax Man,” Bloomberg BNA's Daily Tax Report (September 26, 2016)
  • Kat Gregor, Gabrielle Hirz and Hillel Nadler, “The IRS Needs Help,” Law360 (February 2, 2017)
  • Kat Gregor and Gabrielle Hirz, “A Loose Standard For IRS Summons Enforcement,” Law360 (August 16, 2016) (subscription required)


  • Moderator, “Litigating Tax Issues in Bankruptcy: Possibilities and Pitfalls," Section of Taxation ABA Midyear Meeting (February 8, 2018)
  • Panelist, “Tax Practice & Procedure Monthly New U.K. Law on Failure to Prevent Criminal Facilitation of Tax Evasion,” Federal Bar Association, Tax Practice & Procedure Roundtable (May 2016)
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