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Chicago, Illinois

Service Experience
  • Tax
  • Advisory
  • Tax Reporting & Advisory
  • Risk, Compliance & Controls

Mark A. Sumlin




Executive summary


Mark is a Partner at Grant Thornton, specializing in Enterprise-wide Finance Transformation, bringing more than 20 years of experience both in consulting and large corporate roles. He specializes in the improvement of control managed processes, operational optimization through technology applications, global organization design and crisis management through times of disruption and leadership voids. He also advises clients in matters of alternative operating models, including business process outsourcing, co-sourcing, center of excellence and shared service center design. Mr. Sumlin focuses on strategy development, transaction advisory services and technology solutions to enable enterprise-wide transformation and operational effectiveness.


Prior to joining Grant Thornton, Mark was a Partner with PricewaterhouseCoopers in the Innovation, Tax Reporting & Strategy practice, serving as the National Leader of the Tax Transformation group.


Mr. Sumlin has also spent several years as the Global Leader of Tax Operations in a large multinational, where he oversaw Accounting, Risk Management and Technology. He directly managed a large, cross-border group of individuals in remediation of reporting deficiencies and internal control failures, as well as a complete redesign of global tax function processes, personnel model, shared service center usage and the correlative technology platforms that enabled the organization.


His unique blend of consulting and in-house experiences provide him a perspective that his clients value, with tailored insights and solutions that add value to any organization type and issue set.




Professional qualifications and memberships

  • American Institute of Certified Public Accountants
  • Illinois Society of Certified Public Accountants



Community involvement

  • Mark serves on the PTA Council at Eisenhower Junior High School as Treasurer.  Mark also volunteers at Junior Achievement and through his local church at various charities.




  • Mark received his Bachelor of Science in Accounting from Bob Jones University and his Master of Science in Taxation from the University of Illinois Urbana-Champaign. Mark is expected to receive his MBA in May this year from the University of Chicago.

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