Tax Controversy & Litigation

Overview

McDermott Ranked Tier 1 for US Taxes: Contentious

– Legal 500 US 2024

McDermott’s Tax Controversy & Litigation Group brings extensive experience and in-depth knowledge to help clients resolve tax disputes inside and outside of the courtroom.

From the planning stages of a transaction or reorganization to any challenge brought by a taxing authority, our tax controversy and litigation lawyers are advocacy-oriented. We work with corporations, private equity funds, partnerships, and high-net-worth individuals to develop bespoke solutions that minimize risk, protect interests, and achieve the most favorable outcomes. By partnering with clients across diverse industries, including technology, energy, and life sciences, we gain deep insights into their business, enabling our tax team to strategically advise on specific disputes.

Tax Controversy & Litigation Capabilities

Our Tax Controversy & Litigation Group is uniquely qualified to represent you during all stages of tax disputes and, if necessary, in litigation.

PRE-CONTROVERSY PLANNING

Long before a tax audit begins, our lawyers work closely with clients to spot potential issues and avoid tax controversies. We advise on matters related to:

Protecting privileges
Return filing positions (e.g., uncertain tax positions and reserve analysis)
Document retention
Tax planning positions for audits

Additionally, we help secure rulings from taxing authorities, such as private letter rulings, technical advice, and other determinations, on various tax matters.

IRS AUDITS

We assist with all aspects of Internal Revenue Service (IRS) examinations to obtain favorable outcomes. Some of our work includes:

Developing examination strategies
Negotiating and drafting responses to Information Document Requests
Asserting and defending privileges
Resolving issues with the IRS examination team through audit strategies and presentations

Each examination has its own nuances, and our work may involve behind-the-scenes advice or directly interfacing with the IRS examination team. Our level and manner of involvement is strategic, and we address each examination as part of a holistic approach to federal tax controversy.

IRS APPEALS

When tax issues cannot be favorably resolved during an examination, we represent clients before the IRS’ Office of Appeals (IRS Appeals). Our work includes:

Drafting protests to advocate for our clients’ positions
Conferring with IRS Appeals officers and technical specialists
Negotiating favorable settlements

IRS ALTERNATIVE DISPUTE RESOLUTION PROGRAMS

We resolve matters through the IRS’ various alternative dispute resolution procedures, including:

Fast track settlement
Early referral to IRS Appeals
Rapid appeals process
Post-appeals mediation
Industry issue resolution

We also help with seeking the assistance of the US Competent Authority for treaty disputes under the Mutual Agreement Procedures.

TAX LITIGATION

When settlement is not possible, we resolve tax disputes in litigation before the US Tax Court, federal district courts, the US Court of Federal Claims, and appellate courts across the country.

We have successfully litigated some of the largest and most complex tax cases in the US, including:

“Bet-the-company” tax cases
Cases of first impression
Summons enforcement proceedings and disclosure actions
Challenges to the validity of Treasury Regulations

SUPREME COURT & APPELLATE LITIGATION

Drawing on resources from McDermott’s renowned supreme court & appellate litigation practice, our Tax Controversy & Litigation Group offers a valuable combination of technical tax knowledge and broad appellate experience. Our tax controversy lawyers have successfully represented clients on appeal from lower court decisions in major tax cases and have participated directly in the briefing and argument of cases that are crucial to the development of tax law.

CRIMINAL TAX DEFENSE

We leverage our criminal tax defense experience, extensive knowledge of criminal tax procedure, and strong government connections to achieve the best possible outcome for clients in:

Sensitive audits
Subpoena responses
Search warrants
Voluntary disclosures
Investigations
Plea negotiations
Trials
Sentencings
Appeals

Drawing on our deep understanding of the IRS and the US Department of Justice (DOJ), we proactively advise on upcoming challenges, new legislation, areas of enforcement, and emerging trends, helping our clients develop and strengthen their compliance programs and conduct internal investigations. Our team includes former trial lawyers from the DOJ, the DOJ’s Tax Division, and lawyers who have joined us from US attorneys’ offices.

IRS Success: Franchisee Recoups $3 Million With 100% Tax Penalty Abatement

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Tax Controversy 360

Real-Time Tax Disputes Insights

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National Tier 1 for Litigation and Controversy – Tax

Best Law Firms^® 2025

“McDermott has an excellent understanding of tax law and application to the situations we encounter. They can make complex legal issues understandable and help come to a workable resolution. We rely on the advice we receive extensively.”

– Best Law Firms, Client Reference

Results

Represented an oil and gas company against the IRS in a case before the Tax Court involving a specified liability loss carryback and research and development tax credits
Advised a US-based petroleum refiner on federal, state, and local tax controversies and litigated federal and state tax disputes
Represented a major credit card company with respect to transfer pricing, tax accounting, and foreign tax credit issues in IRS Examinations and IRS Appeals, including with IRS Advance Pricing Agreements
Represented a global technology company protesting proposed transfer pricing adjustments and IRS Appeals
Represented a petroleum products company before IRS Appeals and Collections with an offer-in-compromise requesting relief based on “doubt as to collectibility” and “effective tax administration”