Mark Sims practices in the Business Representation & Transactions Group and works primarily in the federal income tax, business planning and healthcare areas. Mark's federal tax practice involves individual, corporate, S corporation, and partnership tax planning, including advising clients in real estate, new markets tax credit and opportunity zone transactions. He advises public and private companies regarding the tax aspects of mergers and acquisitions and executive compensation matters, including equity and incentive plans, stock option plans, and deferred compensation arrangements. Mark also represents clients on matters before the IRS and state tax agencies. Additionally, he has significant experience focusing on tax issues related to the formation and operation of tax exempt organizations.

Mark serves in a general counsel role for a number of closely held businesses and represents purchasers and sellers of businesses and business interests. His healthcare practice concentrates on business issues facing healthcare providers, including representing physician and dental groups in structuring, purchasing, and selling medical practices. Mark also has extensive experience drafting, reviewing, and negotiating physician employment agreements.

Mark has been an adjunct professor at the University of Cincinnati College of Law and speaks frequently on tax issues. 

Professional and Community Involvement

American Bar Association, Tax and Health Law Sections

Ohio State Bar Association, Federal Taxation Specialty Board

Cincinnati Bar Association, Tax and Health Care Sections, Past President of Tax Section

Hamilton County Development Company, Past Board Member and Past President

Keep Cincinnati Beautiful, Past Board Member and Past President

Christ the King Parish, Finance Committee

St. Rita School for the Deaf, Board Member

Awards & Recognition

AV® Preeminent™ Peer Review Rated, Martindale-Hubbell

Named to Ohio Super Lawyers

Listed in The Best Lawyers in America, 1995-2024

Named to Ohio Leading Lawyers, 2024

  • Best Lawyers (Don't Delete)
  • Peer Review (Don't Delete)

News & Resources

Speaking Engagements


Blog Posts


  • Ohio
  • U.S. Claims Court
  • U.S. Tax Court


LL.M. Taxation, University of Florida Law School, 1981

J.D., University of Cincinnati College of Law, 1980

B.B.A., University of Cincinnati, 1977

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