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Ruben Sislyan focuses his practice on California state and local tax controversies at the audit, administrative, and judicial levels. He has broad experience representing Fortune 500 and middle-market companies, closely held businesses, start-ups, families, and individuals in a wide range of state and local taxes, including corporate franchise/income, personal income, sales and use, property, tobacco, and gross receipts and other local taxes.

Ruben helps clients navigate through all stages of California’s complex administrative tax controversy process. He regularly practices before California’s state and local tax agencies and tribunals, including the Franchise Tax Board, the California Department of Tax and Fee Administration, the State Board of Equalization, the Office of Tax Appeals, and the Los Angeles Office of Finance. Ruben also has experience representing clients in California courts and challenging unlawful taxes.



  • Challenged an unconstitutional property tax disguised as a local business tax, securing a multimillion-dollar judgment for a major oil company.°
  • Represented a major energy sector company in reversing the California Franchise Tax Board’s classification of income from a failed merger as business, rather than nonbusiness, income, saving the company millions of dollars in tax, interest, and penalties.°
  • Represented a grocer in overturning Los Angeles’s long-standing policy of illegally overtaxing wholesalers.°
  • Representation of professional athletes and high-net-worth individuals in state residency disputes, including a major win for a prominent NFL athlete before the California State Board of Equalization.°
  • Represented two global rental car companies in challenging an unlawful tax disguised as a user fee.°
  • Represented a California-based apparel company in securing a seven-figure sales tax reduction.°
  • Represented a medical technology company in a commercial domicile case, wiping out the entire tax assessment in excess of ten million dollars.°

°The above representations were handled by Mr. Sislyan prior to his joining Greenberg Traurig, LLP.

  • Senior Associate, Deloitte Tax, LLP, 2012-2016
  • Judicial Extern, Hon. Peter H. Carroll, U.S. Bankruptcy Court for the Central District of California, 2012
  • Tax Intern, Ernst & Young, LLP, 2011
  • Legal Extern, Internal Revenue Service, 2010

Sukcesy i wyróżnienia

  • Listed, The Best Lawyers in America, "Ones to Watch," Tax Law, 2024


  • LL.M., Taxation, with highest distinction, Loyola Law School, Los Angeles
  • J.D., Loyola Law School, Los Angeles
    • Concentrations in Corporate Law and Tax Law
  • M.A., Economics, University of Southern California
  • B.A., Economics, cum laude, University of Southern California
Posiadane uprawnienia
  • California
  • U.S. District Court for the Central District of California
  • U.S. Tax Court