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Practice Area(s)


  • 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

Other Professional Affiliations

Member, American Bar Association, Section of Taxation

Member, U.S. Council for International Business

Volunteer, Christian Medical & Dental Associations

Government Experience

Attorney Advisor, U.S. Tax Court, Honorable D. Irvin Couvillion, Washington, D.C., 2004-2006

Law Clerk, Sex Crimes Division, Office of the District Attorney, Baton Rouge, LA, 2002-2003

Dianne C. Mehany

Member, Washington, D.C.
(202) 862-5068 | v-card | PDF

Dianne C. Mehany is a Member in Caplin & Drysdale's Washington, D.C., office. She joined the firm in 2010.


Ms. Mehany's practice focuses on international tax planning and controversies, including inbound and outbound tax planning, foreign tax credits, tax treaties, tax audits, and FATCA planning and compliance. She also has experience in tax compliance of individuals, companies and financial institutions in the cross-border context, including FATCA reporting, reporting of interests in foreign trusts, and offshore financial accounts and assets.

Ms. Mehany's practice also encompasses income and succession planning for wealthy individuals and families, including pre-immigration planning and expatriations, 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).
  • Represented pro bono matters through the Houston Bar Association from 2006-2010.

Awards & Rankings

  • Super Lawyers, Rising Star, Washington, D.C., 2017-2018
  • The Legal 500, Recommended, 2016
  • 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

Click here for a full list of media coverage.

Recent Speaking Engagements

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

  • Moderator, Tax Enforcement – U.S. & UK Update: what is around the corner?, U.S./UK Tax Planning 2019, London, November 7, 2019
  • Speaker, Allocation of Trust Distributable Net Income Between Trust and Multistate Beneficiaries, Strafford Publications, October 8, 2019
  • Panelist, To Err is Human, to Forgive Divine: A Guide to Reasonable Cause And Other Defenses to Form 3520 Penalties, 2019 ABA Section of Taxation Fall Meeting, October 5, 2019
  • Chair, The New OECD Global Anti-Base Erosion Proposal, IBA Annual Conference 2019, September 24, 2019
  • Speaker, Inclusion of Capital Gains in Distributable Net Income for Trusts and Estates: Allocations for Optimal Tax Treatment, Strafford Publications, September 19, 2019
  • Panelist, Welcome to International Private Client: Analyzing Foreign Trusts Workshop, 2019 ABA Section of Taxation May Meeting, May 11, 2019
  • The Landscape of Tax Enforcement in the U.S. and UK, U.S./UK Tax Planning, Los Angeles 2019, May 6, 2019
  • Panelist, The Landscape of Tax Enforcement in the U.S. and UK, U.S./UK Tax Planning, New York 2019, May 2, 2019
  • Speaker, Multistate Allocation of Trust Distributable Net Income: Income Sourcing and Apportionment, Strafford Publications, February 21, 2019
  • Panelist, 360 Degree Perspective: U.S. Withholding and Global Information Reporting, ABA Section of Taxation, 2019 ABA Midyear Meeting, January 17, 2019
  • Panelist, Calculating Foreign Trust DNI and UNI: Avoiding Throwback Tax on Undistributed Net Income, Strafford Publications, October 31, 2018
  • Panelist, Dispute Resolution, ICAP, MAP, OECD International Tax Conference, June 4, 2018
  • Presenter, Expatriation Tax, IBC Finance, May 8, 2018
  • Panelist, Trust Distributions to Foreign Beneficiaries: Complex Planning and Calculation Challenges, Strafford, February 27, 2018
  • Panelist, International Tax Reform, American Bar Association Section of Taxation 2018 Midyear Meeting, February 8, 2018
  • Speaker, The Future of US Cross-Border Criminal Tax Enforcement, Cross Border Planning for the Private Client - Asia, August 16, 2017
  • Panelist, U.S. Tax Compliances for Americans Living in India and Remedial Measures for Non-Compliance, Grant Thornton and Caplin & Drysdale, June 14, 2017
  • Panelist, The Pressures on Offshore Jurisdictions, TransTrusts: International Forum 2017, May 5, 2017
  • Panelist, Innovation - The Key to a Strong Economy: A Discussion of Immigration and Tax Policies to Encourage the Development of an Innovative Economy, American Bar Association Section of International Law, April 27, 2017
  • Speaker, Subpart F Income Tax: Its Scope and Application to US Shareholders, ABA Tax Section, January 19, 2017
  • Speaker, Trust Distributions to Foreign Beneficiaries, Strafford, January 5, 2017
  • Speaker, Mastering Form 3520: Reporting Foreign Trust Activities on U.S. Income Tax Returns, Strafford, July 14, 2016
  • Speaker, FATCA: How It Affects Every Practice, American Academy of Attorney-CPAs, June 23, 2016
  • Speaker, Aetna International Customer Forum, Aetna International, November 3, 2015
  • Panelist, Residence: Beyond the Basics, American Bar Association, 2015 Joint Fall CLE Meeting, September 18, 2015
  • Seminar H: The Taxation of Global Families, International Fiscal Association, Basel 2015, September 2, 2015
  • Navigating U.S. Tax Requirements and Strategic Methods of Coming into Compliance, Caplin & Drysdale, Chartered and Ham, Langston & Brezina LLP, U.S. Tax Requirements and Compliance Seminar, March 11, 2015
  • Panelist, A Primer on Tax Treaties, American Bar Association, 2015 Midyear Meeting, January 31, 2015
  • Panelist, How Many Shades of Grey? Current Ethical Issues for Tax Professionals, 66th Annual Virginia Conference on Federal Taxation, June 11, 2014
  • Moderator, First Time on the Bench: Perspectives from Tax Court Judges, American Bar Association, 2014 May Meeting, May 9, 2014
  • Panelist, Meeting the Ethical Challenges of Inbound Controversies, American Bar Association, 2014 May Meeting, May 9, 2014
  • Panelist, Nuts & Bolts Series: International Tax Enforcement: FBARs, FATCA, and More, American Bar Association, 2014 May Meeting, May 8, 2014
  • Panelist, Issue Spotting Across the Globe for Expatriate Executive Packages, American Bar Association, Joint Committee on Employee Benefits Webinar, December 17, 2013
  • Speaker, Advising Clients with International Tax Issues: Form Numbers, PFIC and More, American Law Institute (ALI) CLE, Hot Topics for Accountants & Tax Lawyers: Tax Returns, Advice, & Examination, December 16, 2013
  • Panelist, Leaving the U.S. – It's Very Different from Leaving Las Vegas. Tax Planning for U.S. Persons Living and Working Abroad, American Bar Association, 2013 Joint Fall CLE Meeting, September 20, 2013
  • Panelist, Coping With FATCA If You're Not a Foreign Financial Institution, American Bar Association, 2013 May Meeting, May 10, 2013
  • Speaker, The Ethical Framework - Duties of the Tax Practitioner to the Client and to the System, University of Virginia Tax Foundation, 64th Annual Conference on Federal Taxation, June 7, 2012
  • Speaker, The Road Less Traveled: Exploring Niche Tax Practices, American Bar Association, 2012 May Meeting, May 1, 2012
  • Moderator, The New Application of Transferee Liability, American Bar Association, 2011 Midyear Meeting, January 21, 2011
  • Moderator, Tax Consequences of Disasters, American Bar Association, 2010 Joint Fall CLE Meeting, September 24, 2010
  • Speaker, Four Actions Explained in Forty Minutes, American Bar Association, 2009 Fall Joint Meeting, September 24, 2009
  • Speaker, Forever Ought to be Worth a Lot: Defending Perpetual Conservation Easements, Chamberlain Hrdlicka Law Firm, 2008 Annual Tax Forum, December 17, 2008
  • Panelist, Getting the Most Out of Your Expert Witness in Tax Cases, American Bar Association, 2008 Joint Fall Meeting, September 22, 2008

Click here for a full list of speaking engagements.

Recent Publications

Click here for a full list of publications.