Katy Stone focuses her practice on tax controversy and litigation. She represents financial institutions, multinational corporations, partnerships, tax-exempt organizations and individuals at various stages of federal and state income tax controversies, including audits, administrative appeals and judicial proceedings. Ms. Stone’s practice covers a diverse range of tax issues, including international tax, multistate income apportionments, worker classification, payroll taxes and withholdings, tax-exempt organizations, voluntary disclosures and administrative procedures.

Selected representative matters include:

  • a multinational technology company in connection with an IRS audit of its cost sharing arrangements relating to the development of technology products
  • a professional services company in relation to a third-party subpoena in a tax dispute before the U.S. Court of Federal Claims
  • Amgen Inc. in a transfer pricing case concerning the licensing of complex biopharmaceutical products before the U.S. Tax Court
  • a U.S. financial institution in a Massachusetts state financial institution excise tax dispute before the Appellate Tax Board
  • a professional services company in a New York state income apportionment controversy before the Division of Tax Appeals
  • a multinational technology company in its transfer pricing planning
  • a U.S. telecom company in its multistate income apportionment analysis
  • Brookfield Renewable Partners L.P. in its joint venture with Closed Loop Partners, LLC to establish Circular Services, as well as a related commitment to invest up to $700 million
  • PayPal in its $4 billion acquisition of Honey Science Corporation
  • I-Mab Pharmaceuticals in its $300 million U.S. IPO
  • Western Digital Corporation in connection with a proposal by activist investor Elliott Investment Management L.P. to split the company
  • a New York non-operating foundation in administrative matters during the COVID-19 pandemic

Ms. Stone also dedicates a significant portion of her practice to tax-related pro bono work. She has represented low-income individuals in administrative and controversy matters before the IRS and the California Franchise Tax Board, as well as tax-exempt organizations in administrative and governance matters.

Ms. Stone is co-chair of Skadden’s Palo Alto Family Affinity Group and former chair of the firm’s Palo Alto Associates Committee. From 2020-22, she served as the chief financial officer of Palo Alto High School’s TEAM (Together Everyone Achieves More) nonprofit organization.



  • LL.M., New York University School of Law, 2022
  • J.D., The University of Chicago Law School, 2018 (Doctoroff Business Leadership Fellow)
  • B.A., New Saint Andrews College, 2004


  • California
  • U.S. Tax Court

Katy R. Stone