Seattle, WA

Located in North Seattle, Withum is a leading Seattle CPA firm with a robust ERISA practice, enhanced forensic capabilities and the ability to offer outsourced accounting and cybersecurity services locally and nationwide.

Seattle New Office

Ranked in the top 25 firms in the nation, Withum’s team of passionate professionals offer advisory, tax, audit and assurance services to the Seattle business community…plus a whole suite of advisory solutions that will level up your success. That’s the Power in the Plus!

Seattle Service Specializations

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Outsourced Accounting Systems and Services (OASyS)
SALT-Washington-Updates

Washington State and Local Tax Updates

Do you or your organization operate in multiple states? Do you own property in a variety of states? Washington 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 Washington 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!

Washington SALT Updates

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
Inside Public Accounting Top 100 Firms 2024 logo
Certified Place to Work 2025-2026
Joe-Thiermann_Web

Partner In Charge

Joseph M. Thiermann, CPA

Joe is a partner with over 25 years of specialized audit experience with audits of defined contribution plans, defined benefit plans, health and welfare plans, labor organizations and not-for-profits. He conducts system-wide reviews, designs and implements accounting systems and works on special projects involving system design, expense reporting and compliance, often in conjunction with other professionals to resolve regulatory and general management issues for clients.

Joe is an avid public speaker, having presented at the Annual Conference of the International Foundation of Employee Benefit Plans (IFEBP), the IFEBP Accountants’ Institute and the Oregon Labor Law Conference, and even taught business courses to contractors.

Seattle Leadership

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Partner
Seattle, WA
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Partner
Portland, OR

Withum in the News

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Chelsie Rabon Named 2026 Next Generation in Accounting Winner

Chelsie is a leader in Withum’s San Ramon, CA, office, where she specializes in audits of employee benefit plans, labor organizations and multiemployer benefit plans. She was recognized for her dedication to clients, technical proficiency and ability to help organizations address audit and compliance requirements. Chelsie is deeply committed to fostering the next generation of…

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Los Angeles Business Journal Names Two Withum Partners as Top Advisors in the San Fernando Valley

Chris Passmore and Steve Martini have made a lasting impact across the San Fernando Valley through their leadership, business advisory skills and community involvement. Recognized for helping businesses navigate change, create opportunity and drive growth, they have strengthened the region’s business community while contributing to its long-term economic vitality. Chris Passmore is the Partner-in-Charge of Withum’s…

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Eighteen team members have been promoted to partner across Withum offices nationwide, joining the Firm’s corporate leadership and contributing to its continued growth and success.
Withum Names Eighteen New Partners

Introducing Our 18 New Partners 

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Withum leadership changes 2026
Withum Announces 2026 Firmwide Leadership Transitions

This next generation of leaders step forward at a pivotal time for the Firm, bringing the technical expertise and strategic perspective needed to navigate continued growth, rapidly advancing technology and an ever-evolving industry landscape. Grounded in the Withum Way mentality, they will shape what’s ahead while preserving the culture that remains central to how the…

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