DLA Piper LLP (US) has a comprehensive tax controversy practice handling disputes at the international, federal, state, and local levels. The team advises on civil and criminal tax investigations, administrative proceedings, and litigation before the US Tax Court and federal appellate courts. The practice is led from New York by Ellis Reemer, who is noted for his experience in confidential audits, grand jury investigations, and complex tax litigation. Diana Erbsen brings prior experience from roles at the US Department of Justice and the IRS Advisory Council. Joseph Myszka handles complex tax disputes alongside international tax planning mandates, while Henry Cheng focuses on cross-border tax compliance and controversy matters. Steve Dixon recently joined the team, bringing experience in federal tax disputes. Victoria Gu departed the team in March 2026.
Legal 500 Editorial commentary
Accolades
Client satisfaction: Lawyer & team quality
Client satisfaction: Billing & efficiency
Testimonials
Collated independently by Legal 500 research team.
- ‘The firm has deep experience in tax controversy. Ellis Reemer and Diana Erbsen are excellent attorneys. In recent years, the firm has added several former IRS and DOJ Tax Division lawyers and now has one of the deepest benches in the practice area.’
- ‘Ellis Reemer is a seasoned New York tax controversy lawyer whose direct style is matched by a strong intellect. Diana Erbsen is an extremely bright attorney with valuable DOJ and IRS experience.’
- ‘The team combines deep technical tax expertise with strong procedural capabilities.’
- ‘Diana Erbsen is technically excellent and brings outstanding client management skills.’
- ‘The team is smart, asks thoughtful questions, and consistently delivers a high-quality work product. Billing is fair, and the working relationship is collaborative and efficient.’
- ‘Joseph Myszka is a strong listener who understands our industry and provides practical advice we can rely on. We work well together, which strengthens the overall relationship.’
Key clients
- FTI Consulting
- Gigamon, Inc.
- Hilton Domestic Operating Company, Inc. [Hilton Hotels]
- Kyocera Corporation
- Synopsys, Inc.
- The Brink's Company
- Triangle Peak Partners, LP
- UpHealth Holdings / Thrasys
- YA Global Investments LP
- Yamaha Corporation
Work highlights
Representing Kyocera AVX in a dispute with the IRS concerning entitlement to a deduction related to the IRC § 965 repatriation tax. The matter was initially filed as a refund action in US District Court and later transferred to the US Tax Court following issuance of a notice of deficiency.
Representing YA Global in Tax Court litigation concerning whether offshore investors had income effectively connected with a US trade or business. Following adverse opinions in 2023 and 2024, the team filed an appeal to the US Court of Appeals for the Third Circuit in May 2025.
Representing Thrasys in Tax Court litigation with the IRS. During the proceedings, Thrasys and its parent filed for bankruptcy, resulting in the tax dispute being transferred from the Tax Court to the Bankruptcy Court.
Lawyers
Leading partners
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Practice head
Ellis Reemer; Diana Erbsen
Other key lawyers
Henry Cheng; Steve Dixon; Joseph Myszka