Dan Mayo is a Partner with over 25 years of professional tax experience in federal, international, and financial products taxation.
As the Lead for Withum’s National Tax Services practice, he helps businesses structure their affairs and plan transactions to minimize federal income taxes. He is experienced in mergers and acquisitions, capital markets transactions, and cross-border transactions, and he represents individuals and businesses in tax controversies with the IRS. Dan also serves as an expert witness in litigation involving tax issues
Dan is a recognized expert in the areas of Qualified Small Business Stock (QSBS) and the Employee Retention Credit (ERC), and he co-leads Withum’s ERC Group. He keeps a pulse on federal income tax matters and upcoming legislation, and not only is he a thought leader within the Firm, but he is also an adjunct tax professor at Georgetown University Law Center and a frequent contributor to Forbes, writing on all things tax and sharing best practices for minimizing taxes for businesses and HNW individuals.
Learn more about my professional experience and how I spend my time outside the firm.
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As a tax professor at Georgetown University Law Center and an approved arbitrator for FINRA, Dan has an affinity for sharing his knowledge with others. He is a frequent speaker on webinars and at external tax conferences, and he writes for tax publications like the Daily Tax Report and Tax Notes Today. Previously, Dan served as the Chair of the Banking & Savings Institutions Tax Committee of the American Bar Association’s Tax Section.
Outside of the office, Dan’s hobbies include pickleball, tennis, swimming, and most importantly, spending time with family.
On January 16, 2026, the U.S. Court of Appeals for the Fifth Circuit issued a split decision (2–1) in Sirius Solutions v. Commissioner, a case with significant implications for partnership taxation. The ruling addresses the scope of the self-employment tax exclusion under Internal Revenue Code §1402(a)(13) and could reshape tax planning for limited partners in…
Are you a founder, investor or executive wondering if your business qualifies for powerful tax savings under the Qualified Small Business Stock (QSBS) rules? With recent updates from the 2025 One Big Beautiful Bill Act, commonly referred to as the OBBBA or OB3, understanding your eligibility and maximizing your benefits is more important than ever….
Now is the time to review and consider all of your year-end tax business planning options and strategies for the 2024 tax season. Check it out now.