Who We Are

William S. Duvall, CPA, CVA

Bill is an accounting professional with over 25 years of public accounting experience. He started his career working in security-sensitive areas of the CIA holding advanced clearances. He entered public accounting in 1984 and is licensed as a Certified Public Accountant (CPA) in Virginia, Maryland and North Carolina (certificate number 31902).

Specializing in business valuation and litigation support services, Bill also holds the designation of Certified Valuation Analyst (CVA).  A CVA appraises and values businesses for such reasons as mergers and acquisitions, estate planning, shareholder disputes and divorce matters.  Over many years of valuation and litigation related engagements, Bill has qualified as an expert and testified in General District, Circuit, Federal and Federal Bankruptcy Courts. He has been voted a “Virginia Super CPA” for his business valuations work on numerous occasions.  In addition, he has also been honored with the designation of a “Smart CPA” by Smart CEO Magazine on several occasions.

Bill is a member of the American Institute of Certified Public Accountants (AICPA) and the Virginia Society of Certified Public Accountants (VSCPA), where he is a past President of the VSCPA Northern Chapter. He has spoken nationally for the AICPA and has been published by the AICPA as a contributor to the strategic planning section of the Management of an Accounting Practice Handbook. He is also a member of the National Association of Certified Valuation Analysts.

Bill gives back to his community and profession as well by serving on various boards and professional committees and having served as an officer for local civic and non-profit organizations. He is married with one son and enjoys golf, fishing and the beach.

Regina N. Jessop

As the administrative partner for DuvallWheeler, LLP and with more than 25 years of public accounting experience, Regina’s thorough understanding of the unique needs facing many small employers in today’s business environment is unparalleled. Having started her professional career with the Federal government and subsequently advancing through the ranks of private industry, her experience has included managing the day-to-day operations of both small and medium-sized accounting firms in the Washington DC metropolitan area. Her wealth of knowledge on the how-to’s of running a successful business is now being carried over to DuvallWheeler, LLP.

Regina is actively involved with the Prince William Chamber of Commerce. She was recognized for her continuing efforts by being voted “Chamber Member of the Year for 2008.”

Regina believes in giving back to the community and her profession. In addition to having served on the boards of several professional and non-profit organizations, she is actively involved in a variety of community and fundraising events.

Regina is married, and she and her husband have resided in Manassas for the past 20 years with their canine family.

J. Timothy Mauk, CPA

Tim’s progressive accounting, tax and financial management experience has been developed not only as a CPA in public practice, but also as a CFO and Corporate Controller for companies with annual revenues ranging from $5 million to $80 million.  In addition to working with small and middle-market local businesses, Tim also has extensive experience with rapid growth multi-company environments and mergers and acquisitions.

He is a graduate of George Mason University and a member of the American Institute of Certified Public Accountants (AICPA) and the Virginia Society of Certified Public Accountants (VSCPA).  He serves as secretary/treasurer on the board of Court Appointed Special Advocates of Greater Prince William (CASA) and as treasurer on the board of the Haymarket Gainesville Business Association (HGBA).

Tim is married and enjoys golfing when he can during his free time.  Tim and his wife also share their home with adopted former racing greyhounds.

Shannon D. Hagerich, CPA, MST

Shannon is an accounting professional with over nine years of public accounting experience.  She is a licensed Certified Public Accountant and received her Master’s Degree in taxation from American University.

Shannon has a wide range of professional experience, including individual, corporate, fiduciary, estate and non-profit taxation.  She also has many years of experience in dealing with the Internal Revenue Service and state taxing jurisdictions and often assists clients in resolving various complex issues ranging from unfiled tax returns to disputes over assessments made by taxing authorities.

Shannon has been recognized as a “Smart CPA” by Smart CEO Magazine.

Shannon is a member of the American Institute of Certified Public Accountants (AICPA) and the Virginia Society of Certified Public Accountants (VSCPA).  She gives back to the community by volunteering as an ambassador for the Prince William Chamber of Commerce.  She is an animal lover and also enjoys sports and the outdoors.

Helen G. Madorma, CPA

Helen brings 20 years of experience in public accounting to the DuvallWheeler team.  Having gained her early public accounting experience with the Big 4 of the profession, she brings a unique and valued perspective to our range of service options.  Having also been a business owner, she understands and can relate to the unique and diverse needs of business owners, as well as the changing needs of individual taxpayers. 

Helen received her Bachelor’s Degree in Accounting from George Mason University.  She is actively involved as a board member and officer with the Kiwanis Club of Manassas/Battlefield. 

Helen is married with three boys and one dog, and her interests include nature/outdoor photography and mountain climbing.  Having accomplished five climbs already, she is currently pursuing her goal of completing all 53 peaks.  Helen is also a triathlete.

David C. Lamb, CFE, MSA

David comes to DuvallWheeler after completing his Masters in Accounting from Liberty University and is currently studying for the CPA exam.  He received his undergraduate degree in accounting from the University of Georgia and worked in the profession in the Athens, Georgia, area for several years prior to his relocation to Northern Virginia.

David’s strong background and knowledge in accounting compliments his growing tax skills as he assists with much of the A&A work in the firm and deals with many clients in the small business department.  He is also very active with the consulting practice of the firm and has received his Certified Fraud Examiner (CFE) certification.

David is married with two dogs and is an avid Georgia Bulldogs football fan.  He is a talented golfer and enjoys golfing as well as brewing his own beer and is a cooking enthusiast.

Judy L. Perry

Judy is a degreed accountant with over 15 years of experience as a full-charge paraprofessional, bookkeeper and tax preparer.  She discovered her interest in accounting while working in the accounting department of a large family business and returned to school to get her accounting degree when her youngest child started school.

Over the years, she has continued to gain valuable experience in a variety of accounting systems by working closely with many small business owners and their accounting departments in a variety of industries.

Judy is in charge of DuvallWheeler’s small business accounting department that assists a variety of clients with accounting issues, payroll reports, Quickbooks support and training and accounting procedures.  Judy’s diversified experience has enabled her to become a valuable source that many small businesses turn to for guidance and advice for their day-to-day operations.

Judy is married with two grown children.

Crystal N. Mullins

Crystal  is our “Director of First Impressions.”  When she is not welcoming clients and guests to our office, she handles a variety of duties as an administrative assistant as well as assisting the Firm’s small business accounting department.

Crystal is married with one daughter.