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Meet Our Professionals.

We are your local Pittsburgh area accountants with the majority of our staff being QuickBooks ProAdvisors. Get to know our trusted advisors.

Shamus Brennan CPA


Shamus Brennan is a CPA with over 20 years of public accounting experience at both a Big 4 firm as well as a large regional firm. Shamus joined Dennis Piper in 2012 and became a shareholder in 2016. His areas of concentration are tax compliance and consulting for high net worth individuals and closely-held businesses. Shamus specializes in the Real Estate industry with experience advising and servicing some of the area’s largest developers, owners and investors. Shamus has a BS in Mathematics Education from Waynesburg University and an Advanced Certificate in Accounting from Robert Morris University. Shamus is a member of the American Institute of Public Accountants and the Pennsylvania Institute of Public Accountants.

Shannon Waldron, CPA, CGMA

Advanced Certified QuickBooks ProAdvisor®

Shannon Waldron has over 20 years of experience in both public and corporate accounting. She directs the sales and marketing efforts for the firm and is the lead instructor for our QuickBooks Seminars. As a QuickBooks trainer and lead instructor for our QuickBooks Seminars, she is an Advanced Certified QuickBooks ProAdvisor® and Certified Enterprise Solution ProAdvisor®. Shannon and her team offer comprehensive QuickBooks training and ongoing computer system support services.

Areas of expertise include internal and external audit, IT, system/data conversion, data migration and consulting in a variety of industries. She has held management positions in the retail, service, HVAC, real estate and banking industries, as well as entrepreneurial ventures and franchise ownership. Shannon graduated from Indiana University of Pennsylvania with a Bachelor of Science in Accounting in 1991 and is also a member of the American and Pennsylvania Institutes of Certified Public Accountants and is a Chartered Global Management Accountant.

Brian Beerman, CPA

Beerman, Piper & Associates, LLC

Brian directs our assurance and business advisory practice under the firm Beerman, Piper & Associates, LLC. Brian has 35 years of experience, including 16 years with the assurance and business advisory practice of the national accounting firm, Ernst & Young. Brian has performed the audits of many publicly and privately held companies in a variety of industries including technology, manufacturing, energy, distribution, and non-profit. Brian also provides advisory services on a wide array of business and accounting issues including business acquisitions and divestitures, cash flow forecasting, budgeting, profit improvement initiatives, and internal audit.

Kimberly Deemer

Office Manager

Kimberly comes to Dennis Piper & Associates with over 30 years of experience in finance, banking, insurance, retail management & office administration.  With an Associates Degree in Business Administration & Computers, Kim brings with her a diverse knowledge of numerous computer applications, bookkeeping, accounting and office management skills.  She also is a Certified Pennsylvania Public Notary and performs notary services for Dennis Piper & Associates clients upon request.  Kim serves multiple roles at our firm including office administration, accounts payable, accounts receivable, human resources, tax return delivery, marketing & advertising.

Cleveland Piper, E.A.

Certified QuickBooks ProAdvisor®

Cleveland has been an Enrolled Agent authorized to represent clients before the IRS for 25 years. He has 14 years of experience working as a Controller and Tax Accountant in the state of Maryland. Cleveland’s previous employment has included working as the Controller for J. H. Burton & Sons, Inc. Cleveland graduated from California University of Pennsylvania with a B.A. in Business Administration & Management.

Marian Linton, CPA

Advanced Certified QuickBooks ProAdvisor®

Marian Linton is a Pittsburgh Certified Public Accountant Marian Linton is a Pittsburgh Certified Public Accountant with over 37 years of diverse accounting experience.  Her vast professional work experience which includes general accounting, cash management, accounts payable, accounts receivable, financial and management reporting, federal and multi-state taxes, and personal computer applications. Prior to working with Dennis Piper & Associates, Marian was the General Accounting Manager for MetPath Laboratories, a medical reference laboratory. 

Lisa Henson, CPA

Certified QuickBooks ProAdvisor®

Lisa has over 30 years of accounting experience mainly in the natural resources field. She also has experience in governmental contracts and manufacturing. She has extensive management experience with 16 years of CFO and Controllership roles. Her experience encompasses many areas including general ledger accounting, financial reporting, budgeting, human resources, payroll, benefits plans, and IT. Lisa graduated from West Virginia University with a Bachelor of Science in Accounting in 1988 and obtained her MBA from West Virginia University in 1995.

Mary Quinlisk

Certified QuickBooks ProAdvisor®

Mary comes to Dennis Piper & Associates with a BS in Business Administration & Accounting from Clarion University of Pennsylvania. She has 15 years of experience as a staff accountant in two hospital and rehabilitation systems in the Pittsburgh area. In addition, Mary was self-employed for 14 years providing accounting and payroll services for small to medium-sized businesses. Her experience encompasses all aspects of accounting from general ledger, financial statement and budget analysis to management and controllership responsibilities including accounts payable, accounts receivable and payroll applications. Mary has served as a tax preparer and provided tax planning to individuals in a variety of tax situations. Mary has 20 years of experience working with QuickBooks.

Matt Quinlisk

Office Assistant, Bookkeeper

Matt is currently a student enrolled at CCAC in the Associate’s Degree Accounting program, looking to eventually earn a Bachelor’s Degree and CPA certification.  At Dennis Piper & Associates, he is currently working on his QuickBooks ProAdvisor certifications. His responsibilities include payroll, bookkeeping, accounts payable, accounts receivable, and tax return delivery.

Dennis Piper, CPA, MPA, PFS

Founder of Dennis Piper & Associates PC

Dennis Piper had brought over 30 years of expert accounting experience to Dennis Piper & Associates, P.C., which was founded in 1993.  Dennis retired in December of 2019 and continues to offer consulting assistance.

A Pittsburgh-based CPA, Dennis has helped many corporations, individuals, partnerships, limited liability companies, estates and trusts, non-profits and pension and profit-sharing plans. He provided exceptional business advisory, tax compliance and tax consulting services to his clients and was recognized as a Western Pennsylvania Financial Services Champion. Most importantly he created strong partnerships by taking the time to fully understand and meet clients’ business operations, information and accounting goals.

Before starting his firm, Dennis served as controller for a large distribution company. This experience gave him clear insight into what it takes to be a successful entrepreneur and business leader.

How can we help you achieve your business goals? Call 412-826-8600 to schedule a Free Consultation or click here to email Shamus Brennan.

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