About William

William Souter is a Tax & Business Services director in the Firm’s Portland, Maine, office. Mr. Souter joined Marcum LLP in 2019 via the merger of Dawson, Smith, Purvis & Bassett, P.A. (DSPB) into Marcum’s New England Region. Mr. Souter has significant experience in tax compliance, planning, and consulting for privately owned corporations, partnerships, and individuals. He also performs reviews and compilations of financial statements and assists clients with all aspects of accounting and tax matters.

Professional & Civic Affiliations

  • American Institute of Certified Public Accountants (AICPA)
  • Maine Society of Certified Public Accountants (MSCPA)
  • Carlisle Charitable Foundation, board of directors and treasurer
  • Rotary Club of Saco Bay, board of directors and operations treasurer


Income Tax

Industry Focus

Professional Services


Master of Science in Taxation
Thomas College

Bachelor of Science in Accounting
University of Southern Maine