Dianne C. Mehany
Caplin & Drysdale
Dianne C. Mehany Member

P: (202) 862-5068

F: (202) 429-3301

Washington, D.C. Office


Dianne C. Mehany is a Member in Caplin & Drysdale's Washington, D.C., office. She also serves on the Firm’s Board of Directors.


Ms. Mehany's practice focuses on international tax controversies and planning, including tax audits in the cross-border context, inbound and outbound tax planning, foreign tax credits, tax treaties, tax audits, and planning and compliance with respect to Puerto Rico’s Act 60 (formerly Act 20:22). She also has experience in tax compliance of individuals, companies and financial institutions in the cross-border context, including FATCA reporting, reporting of ownership or beneficiary interests in foreign trusts, offshore financial accounts and assets.

Ms. Mehany's practice also encompasses income tax and succession planning for wealthy individuals and families, including pre-immigration and pre-expatriation planning, and foreign trusts.

In addition to advising clients in these areas, Ms. Mehany has extensive experience advising individual and corporate clients in federal civil and criminal tax controversy matters. She guides clients through all stages of IRS disputes, including preparing protests of IRS actions, representing clients at appeals conferences, filing petitions in the Tax Court and complaints in District Court, and assisting with trial matters and settlement discussions.  Moreover, Ms. Mehany has counseled individual clients and financial institutions on the U.S. government's investigation of undisclosed foreign assets, particularly with respect to the classification of foundation and trust structures.


  • Served on the trial team, who achieved a multi-million dollar victory in the Tax Court regarding the deductibility of a termination fee.
  • Achieved a summary judgment on research credit for privately-held company.
  • Successfully obtained private letter rulings granting Section 9100 relief for changes in accounting method, retroactive applications of registration, and retroactive elections.
  • Served on the trial team for Avenell v. Commissioner, T.C. Memo 2012-32, which successfully defended the taxpayer against allegations of fraud by the IRS.
  • Member, Wex S. Malone American Inn of Court (one of ten from the graduating class invited for membership due to outstanding performance in LSU Trial Advocacy Program).

Practice Area(s)

Awards & Rankings

  • Super Lawyers, Rising Star, Washington, D.C., 2017-2018, Washington, D.C., 2020
  • The Legal 500, Recommended, 2016, 2020
  • The American Lawyer's Global Legal Award, Global Dispute of the Year: Investigations, Swiss Tax Settlements, 2015
  • Nolan Fellowship, American Bar Association, Section of Taxation, 2015-2016

Recent News

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Speaking Engagements

Ms. Mehany speaks before many professional associations and conferences. Her recent engagements include:

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Recent Publications

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  • LL.M. in Taxation, Georgetown University Law Center, 2006
  • J.D., Louisiana State University Law Center, 2004, Chancellor's List; Louisiana Law Review
  • LL.B., Louisiana State University Law Center, 2004
  • B.A., Southern Arkansas University, 2001, cum laude; Alpha Chi Honor Society; Outstanding Leader of the Year Award (2000)

Bar and Court Admissions

  • District of Columbia
  • Texas
  • California (inactive)
  • U.S. Tax Court
  • U.S. District Court, Southern District of Texas
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