Thomas Cullinan

Practice Areas

Tax

Tax Controversy & Litigation

Career

Tom Cullinan is a Shareholder in the Firm's Atlanta office. Tom joined the Firm from the IRS, where he served as the Counselor to the IRS Commissioner and then as the acting IRS Chief of Staff.

While at the IRS, Tom was a member of the Commissioner’s core leadership team, and he advised the IRS Commissioner on the most critical issues facing the agency, including the IRS strategic plan and budget, staffing, internal operations, enforcement of tax laws and service to taxpayers. He was particularly involved in high-level enforcement issues. Among other things, Tom either conceived or helped launch the Office of Fraud Enforcement, the Office of Promoter Investigations, and the Joint Strategic Emerging Issues Team, all of which should be key IRS enforcement tools in the coming years. Tom also helped implement various policies pertaining to cryptocurrencies and served as an invited IRS representative to several Financial Stability Oversight Council meetings regarding cryptocurrencies.

Before joining the IRS, Tom spent twenty years as a tax attorney representing taxpayers in tax controversy matters. He has represented hundreds of taxpayers, including low-income individuals in pro bono matters, high net-worth individuals, partnerships, trusts and estates, and corporations in IRS audits, administrative appeals, and litigation, on a wide variety of tax issues often with significant amounts at issue. Tom pursues every possible opportunity to resolve tax disputes and is adept at negotiating acceptable resolutions. Yet, litigation is sometimes inevitable and he has a notable track record in that regard.

Tom works in the Firm’s tax controversy practice where he draws on both his extensive background representing taxpayers and his deep knowledge of the IRS organization, operations, and procedures.

Professional Memberships

Member, Internal Revenue Service Advisory Council (IRSAC) (2015-2017), and Chair of the Large Business & International (LB&I) Subcommittee (2016-2017)

Member, Court Procedure and Practice Committee, American Bar Association Section of Taxation (2002 – present), Former Chair, Tax Shelter Litigation Subcommittee

Member, Civil and Criminal Tax Penalties Committee, American Bar Association Section of Taxation (2003 – present), Former Chair, Civil Penalties Subcommittee.

Member, Administrative Practice Committee, American Bar Association Section of Taxation (2003 – present)

Fellow, American College of Tax Counsel (2014 – 2019, 2023-present)

Former Member, Board of Governors, Court of Federal Claims Bar Association (2008 – 2010)

Publications

"IRS Staff Exodus Expected to Curb Future Hiring Efforts," Tax Notes, May 12, 2025

“Turnover on Downs: The IRS’s Rejection of NIL Collectives as Tax-Exempt Entities,” Sports Business Journal, May 5, 2025

“Turnover Is Coming to the Justice Department Tax Division,” Tax Notes, February 18, 2025

"What To Do If the IRS Denies Your ERC Refund Claim," Forbes, August 6, 2024

"How To Litigate ERC Refund Claims," Forbes, July 1, 2024

"IRS Likely To Increase Scrutiny On The Puerto Rico Act 22 Tax Break," Forbes, June 26, 2024

"What's Next for ERC Refund Claims Pending With The IRS?", Tom Cullinan - Forbes, May 23, 2024

“Due Process Analysis of Proposed Retroactive Changes to the ERC,” Tom Cullinan, Sam Kuzniewski and Jala White -Tax Notes Federal, March 25, 2024

“A primer on IRS tax avoidance promoter penalties,” Tom Cullinan and Erin Hines - Accounting Today, March 22, 2024

"Understanding The IRS' Heavy-Handed Interpretation Of Tax Fraud," Tom Cullinan - Forbes, February 10, 2024

"Multiple ERC Clocks are Ticking – What To Do Before Time Runs Out", Tom Cullinan - Forbes, January 24, 2024

“IRS Settlement Initiatives Can Improve Compliance,” Tom Cullinan - Tax Notes Federal, January 1, 2024

“A Plain-Meaning Analysis of the ERC” Tom Cullinan and Sam Kuzniewski - Tax Notes Federal, November 6, 2023

“IRS to List the Monetized Installment Sale — What Now?” Tom Cullinan, John Kirbo and Erin Hines -Tax Notes August 28, 2023

“Some CRATs Are in the Crosshairs, Yet CRTs Remain Viable” Tom Cullinan, Scot Kirkpatrick, Steve Wyatt, Asher Fried and Emily Dabney - Tax Notes Federal and Tax Notes State, August 7, 2023

“How to face the IRS attacks on Malta pension plans” Tom Cullinan, Kevin Sweeney and John Kirbo - Accounting Today, July 25, 2023

“The Case for a Statute of Limitations for Promoter Penalties” Tom Cullinan - Tax Notes, July 13, 2023

"Emerging Issues in Tax Compliance After IRS Funding Increase” Tom Cullinan and Juan Vasquez, Jr. - Tax Notes Federal, May 8, 2023

IRS Budget Increase: Early Activity Shows a Focus on the Employee Retention Credit, Malta Pension Plans, Monetized Installment Sales, and Other Emerging Issues for Tax Enforcement, Vol. 25, Issue 3 of Journal of Tax Practice & Procedure, Fall 2023

Education