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William Greco

William-Greco Associate

William Greco



Washington, D.C.
T: 202.875.8000, ext. 207
F: 202.844.3500

Will Greco joined Kostelanetz LLP in 2021 after clerking for the Honorable Mark V. Holmes of the United States Tax Court. He graduated cum laude from Harvard Law School in 2020. His practice focuses on civil tax controversy.

Prior to joining Kostelanetz LLP, Will assisted Judge Holmes in writing opinions and orders in cases involving issues such as valuations of real property, Collection Due Process, civil penalty approval processes, and complex, multi-million-dollar tax-evasion schemes. Notable matters that Will worked on included an opinion finding that a conservation easement was worth at least as much as the $5 million charitable donation deduction the taxpayers had claimed, and an opinion finding a taxpayer liable for tax and penalties on nearly $16 million in income earned through the promotion of several tax-evasion strategies over ten years. He also helped draft an opinion resolving a question of first impression about the duties of IRS Appeals officers to review offers-in-compromise during Collection Due Process hearings.

As a student at Harvard Law School, Will served as a Student Attorney with the Federal Income Tax Clinic. In this role, he represented low-income taxpayers in their disputes with the IRS. His work included preparing offers-in-compromise, requests for audit reconsideration, a request for innocent spouse relief, and helping an exonerated individual obtain a refund for tax on his wrongful incarceration compensation. In addition to his work in the Tax Clinic, Will also served as a volunteer tax preparer for Harvard TaxHelp, as a Principal Senior Editor for the National Security Journal, and as a research assistant for Professor David Rosenberg examining how procedural mechanisms in tort law create ex ante incentivizes for medical device manufacturers.

Will graduated summa cum laude from Georgetown University in 2015 with a major in Government and a minor in Italian. He was a member of Phi Beta Kappa, the Georgetown Scholars Program, and the Philodemic Society, one of America’s oldest literary debate societies. In 2023, he was invited to join the J. Edgar Murdock Inn of Court.

Georgetown University, B.A. (2015), summa cum laude
Harvard Law School, J.D. (2020), cum laude

District of Columbia

New York State

U.S. Tax Court