Overview
Caitlin Tharp's multidisciplinary practice focuses on tax controversy, ERISA, and employee benefits, covering both litigation and counseling in those areas.
Caitlin has more than a decade of experience in handling disputes with tax authorities, both at the administrative level and in litigation. Caitlin has represented clients in IRS examinations, achieved full IRS concessions at IRS Appeals, and resolved taxpayer's administrative delays with the IRS. Caitlin’s litigation experience spans all forums for tax disputes, having litigated cases before the Tax Court, Court of Federal Claims, various appellate courts, and federal district courts across the country. These disputes have included challenges to regulations and subregulatory guidance, the economic substance doctrine, excise taxes, alternative energy tax credits, captive insurance, the employee retention credit, and cross-border transactions.
Caitlin’s ERISA experience includes litigating alleged breaches of fiduciary responsibility, prohibited transactions, and withdrawal liability. She has a particular focus in the valuation of closely held businesses from her defense of clients against allegations of inadequate consideration in ESOP transactions. Caitlin also counsels employee benefit funds on plan administration and compliance with ERISA and Internal Revenue Code requirements.
Caitlin is a frequent speaker and writer on emerging issues in tax controversy and practice, including the use of artificial intelligence both by practitioners and by the IRS in tax enforcement. Caitlin has served as a Vice Chair of the Tax Practice & Technology Committee of the ABA's Tax Section, and she was named a 2023-24 John S. Nolan Fellow by the ABA Tax Section, a distinction awarded to lawyers who have demonstrated leadership qualities and active involvement in the ABA Tax Section.
- District of Columbia
- Virginia
- US Tax Court
- US District Court, District of Columbia
- US Court of Appeals, District of Columbia
- US Court of Appeals, Federal Circuit
- US Court of Federal Claims
- LL.M., Georgetown University Law Center, 2016, with distinction, Taxation
- J.D., Georgetown University Law Center, 2015
- B.A., Stanford University, 2012
Areas of Work
Representative Matters
- Lead counsel in refund action in Court of Federal Claims involving foreign tax credits and the high tax kick-out exception.
- Won refund action as trial counsel on behalf of principal in contract manufacturing arrangement in IRS dispute concerning the Section 199 domestic production activities deduction. Meredith Corp. v. United States, 447 F. Supp. 3d 805 (S.D. Iowa 2020); 405 F. Supp. 3d 795 (S.D. Iowa 2019); 433 F. Supp. 3d 1109 (S.D. Iowa 2019).
- Achieved 99% IRS concession in alleged ESOP prohibited transaction case docketed in Tax Court.
- Trial and appellate counsel in Court of Federal Claims case involving the IRS’s assertion of transferee liability for a sale of corporations holding appreciated assets. Dillon Trust Co. LLC v. United States, 168 Fed. Cl. 228 (2023).
- Trial and appellate counsel in a Tax Court case involving an IRS challenge to several million dollars of tax credits for the production of landfill gas as a nonconventional fuel under Section 45K. Green Gas Delaware Statutory Trust v. Comm'r, 147 T.C. 1 (2016), aff'd, 903 F.3d 138 (D.C. Cir. 2018).
- Won 100% IRS concession for pharmaceutical company in IRS Appeals regarding whether rebates from US drug manufacturers constitute income effectively connected with the United States for tax purposes.
- Won 100% IRS concession for energy company in IRS Appeals regarding refund claims for alternative fuel excise tax credits.
- Won 100% IRS concession for healthcare company in IRS Collection Due Process Hearing for failure to pay and failure to file penalties.
- Represented high-net-worth individuals in IRS examination involving at-risk amounts for use of partnership losses.
- Advised Fortune 500 company regarding qualification of captive insurance policies as insurance for federal tax purposes.
Speaking Engagements
- "Deploying Technology and AI in Tax Cases," PLI's Tax Controversy 2026: Navigating the New Enforcement Landscape, March 23, 2026
- "Tax in the Age of AI and Digital Assets," IBA's 14th Annual London Finance and Capital Markets Conference, January 27, 2026
- "The Benefits and Detriments of Using Artificial Intelligence in Tax Practice," NYU Tax Controversy Forum, June 26, 2025
- "The Growing Use of Technology in Tax Administration," Tax Policy & Practice Symposium, May 16, 2025
- "Telegraph, Telex, and Microfiche: When Discovery of 'All Documents' Goes Too Far," ABA Section of Taxation May Meeting, May 9, 2025
- "How to Treat Data for Tax Purposes," ABA Section of Taxation Midyear Meeting, February 19, 2025
- "ABC: AI, big data and crypto," IBA's 14th Annual London Finance and Capital Markets Conference, January 21, 2025
- "Artificial Intelligence: Hot Topics,” DC Bar Tax Conference, January 15, 2025
- "Ethics of Using Artificial Intelligence in Tax Practice," 59th Annual Southern Federal Tax Institute, October 23, 2024
- "Artificial Intelligence, ChatGPT & Circular 230," NYU Tax Controversy Forum, June 28, 2024
- "Ethics of Using Artificial Intelligence in Tax Practice," FBA Insurance Tax Seminar, May 31, 2024
- "Structural Changes in the Economics of Tax Law with the Rise of A.I.," D.C. Bar Tax and Audits Litigation Community, April 18, 2024
- "The Structure of Revolutions in Taxation and the Law: Paradigm Shifts Caused by Artificial Intelligence," Section Luncheon & Plenary Session, ABA Section of Taxation Midyear Meeting, January 20, 2024
- "The Power of Metadata: Challenging Penalties under Sec. 6751(b). What to Look For, Ask For, and How to Challenge the Presumption of Regularity," ABA Section of Taxation Midyear Meeting, January 19, 2024
- "Will Artificial Intelligence Take Over Tax Practice?," New York State Society of CPAs Taxation of Financial Instruments Conference, January 9, 2024
- "Artificial Intelligence in Tax Practice," New Mexico Tax Conference, December 13, 2023
- "Considerations Raised by Broad Use of AI Tools in Practice," 2023 Annual Meeting of the California Tax Bar and California Tax Policy Conference, November 1, 2023
- "Is this thing on? Ethics and Modern Technology in Tax Practice," ABA Section of Taxation Philadelphia Tax Conference, November 15, 2023
- "AI and Tech Privacy: An International and U.S. State Tax Update Tech Session Webinar," New York State Society of CPAs, July 19, 2023
- "AI in Tax: Possibilities and Challenges," Tax Analysts Webinar, June 6, 2023
- "Key Developments in Tax Controversy," FBA Insurance Tax Seminar, June 1, 2023
- "Will Robots Replace Lawyers? The Ethics of Lawyers Using ChatGPT," ABA Section of Taxation May Meeting, May 5, 2023
- "Taxing the Metaverse," ABA Section of Taxation May Meeting, May 5, 2023
- "Technological Advancements in Tax Practice and the Impact of the Inflation Reduction Act on the IRS"s Capabilities and Service", ABA Section of Taxation Fall Tax Meeting, December 6, 2022
- "Taxing the Metaverse: The Next Frontier of Digital Asset Transactions", ABA Section of Taxation Fall Tax Meeting, October 14, 2022
- "Technological Advancements in Tax Practice and the Impact of the Inflation Reduction Act on the IRS"s Capabilities and Service", ABA Section of Taxation Fall Tax Meeting, October 14, 2022
- "The ‘beyond taxes" for the "beyond universe": taxes in the metaverse", International Bar Association, The New Era of Taxation Conference, September 16, 2022.
- "The Metaverse: Ethical Considerations for Tax Practitioners," ABA Section of Taxation May Meeting, May 13, 2022
- "Update on Taxation of Outbound Transfers of Foreign Goodwill and Going Concern Value," Lorman Education Services Webinar, February 23, 2017
- "Navigating the Alternative Minimum Tax for Individual and Corporate Taxpayers," Lorman Educations Services Webinar, May 23, 2016
News & Publications
Client Alerts
June 2026
Focus on Tax Controversy Newsletter
Another Circuit Invalidates an IRS Listing Notice
July 15, 2024
By: Caitlin R. Tharp
Media Mentions
May 13, 2024
Media Mentions
Law360 Quotes Caitlin Tharp in Article About the Future of Artificial Intelligence in Accounting
January 25, 2024
Media Mentions
Tax Notes Quotes Caitlin Tharp on Potential IRS Procurement of AI Operations Platform
December 12, 2023
Resources
Focus on Tax Controversy Newsletter
IRS Revises Voluntary Disclosure Form with Expanded Cryptocurrency Section
March 2022
By: Caitlin R. Tharp
Exempt Organizations Advisory
IRS Summarizes 2021 Exempt Organization Accomplishments
January 6, 2022
Exempt Organizations Advisory
IRS Changes Reporting Requirements for Management Company Services
December 15, 2021
Exempt Organizations Advisory
LLC Qualification for Section 501(c)(3) Recognition
October 22, 2021
By: Caitlin R. Tharp
Exempt Organizations Advisory
Supreme Court Strikes Down California Donor-Disclosure Rules for Charities
July 1, 2021
Exempt Organizations Advisory
IRS Issues Updated Compliance Initiatives for Exempt Organizations
April 5, 2021
Exempt Organizations Advisory
Treasury Report Encourages Increased Identification of Unrelated Business Income by IRS Exam
March 3, 2021
Exempt Organizations Advisory
Final Regulations on Exempt Organization Excess Compensation Excise Tax
January 12, 2021
Events
Seminars & Events
Year End Tax Conference and Celebration
December 6, 2021
Speakers: Alan Cohn, Zvi Hahn, Aaron P. Nocjar, Caitlin R. Tharp, Beth D. Tractenberg, Amanda Pedvin Varma, Lisa M. Zarlenga
Webinars
What Employers Need to Know: Employment Provisions in the CARES Act
May 15, 2020
Speakers: Lisa M. Zarlenga, Kate Jensen, Caitlin R. Tharp
Webinars
Qualified Opportunity Zones: What You Need to Know About the Proposed Regs
May 7, 2019
Speakers: John Cobb, Aaron P. Nocjar, Caitlin R. Tharp, Lisa M. Zarlenga
Noteworthy
- Best Lawyers in America, "Ones to Watch," Tax Law and Litigation & Controversy, Tax (2026)
- Super Lawyers, "Rising Stars," Tax Law (2024-2025)
Professional Affiliations
- Former Vice Chair, Tax Practice and Technology Committee, Taxation Section, American Bar Association
- Advisory Committee Member, Federal Bar Association, Insurance Tax Seminar
- Member, Nominating Committee, American Bar Association Section of Taxation
- John S. Nolan Fellowship, American Bar Association Section of Taxation (2023-24)