Tax Services
Whippany, NJ
Located in the heart of Morris County, minutes from Morristown Business District, Withum is one of New Jersey’s top-ranked accounting and advisory firms, providing reliable audit, tax and consulting services to businesses locally and nationwide.
Withum’s Whippany office has an industry focus on financial services, technology, healthcare, manufacturing, distribution & logistics and private equity. With an onsite state-of-the-art cybersecurity facility, Withum’s CPAs and professionals provide quality accounting services…plus a suite of advisory solutions to help businesses grow and thrive with the personal touch they deserve. That’s the Power in the Plus!
(973) 898 9494
Whippany Service Specializations
Accounting Advisory and Financial Reporting
Audit Services
Employee Benefit Plan Audits
Private Client Services
Wealth Management
Forensic and Valuation Services
Transaction Advisory
Cybersecurity
New Jersey State and Local Tax Updates
Do you or your organization operate in multiple states? Do you own property in a variety of states? New Jersey State and Local Tax (SALT) laws are always changing and understanding the nuances of the states that you own or operate in is challenging. In these New Jersey resources, you’ll find just a dash of the most up-to-date details on rules and regulations as state and local tax changes happen by state!
Industries We Focus on in Whippany
Withum in the Whippany Community
The cornerstone of our region is a thriving, connected business community that supports one another and comes together in times of need. Withum’s Whippany team members live here, work here and are dedicated community servants. Whether through food drives, sponsorships, volunteering, participating in activities or giving back to the many not-for-profit organizations in the area, our communities remain one of Withum’s most essential core values.
Beyond the Region
- Inside Public Accounting Top 100 Firms – 22nd Largest Nationally
- Accounting Today Top 100 Firms – 22nd Largest Nationally
- Great Place to Work® – Fortune Best Workplaces for Parents and Women
- Vault Top 25 Accounting Firm
Partner In Charge
Zsia Rosmarin, CPA, MSBased in the firm’s Whippany office, Zsia is a Partner and Team Leader of the firm’s Technology and Emerging Growth Services tax practice with over 20 years of professional experience specializing in taxation including private and publicly held multistate and multinational companies. She has a deep expertise assisting corporate clients with ASC 740 Tax Provisions and Tax Compliance.
Zsia leads the Tax Tech and Emerging Growth Industry Group where she consults on a wide variety of related tax issues including diligence ready assessments, secondary transactions, qualified small business stock, tax credits and incentives (i.e. R&D, excelsior, QETC), state taxes including sales tax and international taxes. Zsia is the Founder and leader of the Firm’s Women in Technology Group.
She resides in Somerset County, NJ. Previously, she was a partner at a large national accounting firm and a senior manager at a “Big Four” firm.
Whippany Leadership
Partner, Service Leader
Whippany, NJ
Partner, Service Leader
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Partner, Service Leader
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Industry Leader, Partner
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Industry Leader, Partner, Practice Leader
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Whippany, NJ
Industry Leader, Partner
Whippany, NJ
Partner, Practice Leader
Whippany, NJ
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Partner
Whippany, NJ
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Whippany, NJ
Industry Leader, Partner
Whippany, NJ
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Industry Leader, Partner
New York, NY
Withum in the News
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The new site emphasizes clarity, speed, and accessibility—making it easier for users to find relevant content, explore the Firm’s services, and connect directly with Withum’s people and expertise. The Firm’s newly redesigned website reflects a shift in delivering insights digitally by aligning user experience, modern search behavior and growth strategy under a single, purpose-built platform. More than a visual refresh, the…
Kelsey Thomas Named Opus Connect’s 2025 Woman of the Year
This annual recognition honors a member who demonstrates exceptional commitment to the Opus Connect community through consistent participation, leadership and meaningful support of peers. Kelsey was recognized for her commitment to advancing the industry and its community through an M&A lens. Throughout her over 15-year career in public accounting, Kelsey has distinguished herself through seasoned…
Linda Howard Named to Women in CX’s Awesome Women to Follow in CX List
Linda is an active member of Women in Client Experience, Women of Withum and the Association for Accounting Marketing’s Client Experience Circle. She believes in building networks and sharing best practices to strengthen client and team member service experiences. “Linda has been a driving force in shaping what a client experience program will look like at Withum….
BINJE Names Marcus Dyer to 2026 Best Black Business Leaders List
Marcus draws on his law background to represent clients in commercial and tax disputes before state courts, Federal District Court and the United States Tax Court, frequently resolving matters through alternative dispute resolution rather than litigation. As an industry thought leader, Marcus contributes to a wide range of publications, helping businesses and individuals navigate high-risk…
Withum Celebrated New Orange County Office With An Open House
The space, which officially opened in December 2025, offered guests sweeping panoramic views of the region as they toured the thoughtfully designed team collaborative spaces, modern amenities and community spaces that echo Withum’s culture and values. The striking backdrops of the Irvine business hub, Orange County canyons, San Joaquin Hills, Saddleback and San Bernardino Mountains…
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