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William Marx Jr.




Executive summary


Bill Marx is Grant Thornton's leader in the D.C. market. He previously served as a Tax principal and the National Managing Principal for Tax Reporting & Advisory services.


The TRA practice is primarily involved with tax accounting, compliance and planning for complex and dynamic businesses. Prior to joining Grant Thornton, Bill had relevant experiences in both public accounting and industry, including serving as the tax director for a multinational, publicly-traded company.


Bill’s primary goal is to help his clients’ businesses succeed through timely and effective tax planning and compliance services. He leads teams that provide distinctive client service through a commitment to innovation, quality, and collaboration.



Professional qualifications and memberships

  • Bill is a member of the American Institute of Certified Public Accountants and the Pennsylvania Institute of Certified Public Accountants. He is also a member of the Advisory Board for the Philadelphia Tax Conference, a nationally recognized tax seminar co-sponsored by the American Bar Association, and was the co-chair of the 2013, 2014, and 2015 conferences.


Community involvement

  • Bill is a board member and treasurer of the Philadelphia School Partnership (PSP), a non-profit organization with a mission to improve outcomes for low-income students and respond to the demand of families by expanding access to great schools.


Presentations and publications

  • Bill has been very active over his career with teaching about taxes in both internal and external CPE classes, including FEI, TEI, and ABA sponsored conferences. Bill has been quoted several times in popular and tax news media in regards to tax legislation or similar matters, including in The Wall Street Journal (Dec. 17, 2017), Tax Notes Today (April 13, 2020), and IR Magazine (Aug. 16, 2021).



  • Bill earned his master’s degree in taxation from the University of Tulsa in 2006. He received his BS in Education from the Pennsylvania State University in 1995, and his BS in Accounting from the Pennsylvania State University in 1998.

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