John Horne is a Tax Controversy associate in Mayer Brown's Washington DC office.

John focuses his practice on tax disputes and transfer pricing matters. He represents taxpayers at all levels of federal tax controversy, including IRS audits, administrative appeals, competent authority, and litigation before the United States Tax Court. His experience includes controversies with advance pricing agreements, transfer pricing, and debt-equity characterization.

John received his JD magna cum laude from the University of Kentucky Law School where he was Order of the Coif. Prior to joining Mayer Brown, he served as law clerk and attorney advisor to Hon. Joseph R. Goeke of the United States Tax Court.

Tax Controversy Team of the Year


  • Eaton Corporation v. Commissioner of Internal Revenue, T.C. Docket No. 5576-12 (IRC § 482 reallocations and the cancelation of advance pricing agreements).
  • Tyco Electronics Corp., et. al v. Commissioner of Internal Revenue, T.C. Docket Nos. 16651-13, 16652-13, 16653-13, 16654-13, 16655-13, 16656-13, 16657-13, 16658-13, 16659-13, 16660-13, 16661-13, 16662-13, 16663-13, 16664-13, and 19556-13 (debt-equity characterization).


University of Kentucky College of Law, JD, magna cum laude

Order of the Coif

Certified Public Accountant

University of Kentucky, MS

University of Kentucky, BBA, cum laude


  • District of Columbia
  • Kentucky