Your Trusted Full-Service CPA Firm,
Built for You!


  • Financial Statement Audit/Review/Compilation 
  • Business and Personal Income Tax Preparation 
  • Strategic Tax Planning Implementation
  • Business Succession Planning 
  • Transaction & Business Consulting  
  • IRS Representation 


Let’s face it. The public accounting industry has pivoted to an assembly-line approach where clients and employees are churned through a conveyer belt. MB&A was born in 2023 to combat the status quo. The Company’s founders were formerly partners at one of the largest public accounting firms in the world. MB&A’s core purpose is to foster long-term relationships with its clients and colleagues through a personalized, high touch point environment. Our hands-on forward-looking approach to servicing an exceptional group of clients in New England naturally creates ample opportunity for team members to accelerate their career trajectory and clients to add to their bottom line.

Charlie Mamacos, CPA, MST

Charlie Mamacos, CPA, MST

Charlie has 14 years of experience servicing businesses in the construction, real estate, hospitality, and technology industries. Charlie has vast experience providing income tax preparation services, implementing tax minimization strategies, developing strategic exit planning solutions, and representing clients before the IRS. Charlie’s integrated approach to servicing closely-held companies and their shareholders provides his clients with the holistic vision needed to capitalize on a constantly evolving tax landscape.

Masters in Taxation, Bentley University
Bachelors in Accounting, Bentley University

John Bysiewicz, CPA, MBA

John Bysiewicz, CPA, MBA

John has over 15 years of experience servicing clients in the construction, real estate, M&D, technology and ERISA sectors. He focuses on privately held clients, assisting them with audited, reviewed or compiled financial statements, along with providing clients assistance with business strategy, forecasting, bank and surety relationships, tax planning and succession planning, including consulting on M&A deals, internal buyout structuring or passing the business down to the next generation.

MBA, Babson College
Bachelors in Accounting & Finance, UMass of Boston


  • Construction
  • Real Estate
  • Hospitality & Restaurants
  • Manufacturers & Distributors
  • Technology/SaaS
  • ERISA Audits
  • High Net-Worth Individuals

Mamacos, Bysiewicz & Associates, LLC
Riverside Center
275 Grove Street, Suite 2-400
Newton, MA 02466


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