Tax Services
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.
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!
(206) 522 6370
Seattle Service Specializations
Assurance and Accounting
Forensic and Valuation Services
Cybersecurity
Outsourced Accounting Systems and Services (OASyS)
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!
Industries We Focus on in Washington
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
Joseph M. Thiermann, CPAJoe 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
Withum in the News
ROI-NJ Names Withum Leaders to Annual Power List
Pat Walsh Pat Walsh, Managing Partner and CEO, has led numerous firmwide strategic initiatives focused on best practices, client experience and technology. He leads Withum’s national growth strategy and client service initiatives, with a focus on innovation, talent development and expanding the Firm’s advisory capabilities to meet clients’ evolving needs. Pat was recognized for his…
Withum Recognized with Cigna Healthy Workforce Designation™
As a people-first organization, the Firm offers a competitive Total Rewards benefits package with unique perks for Withum team members, recognizing wellness extends beyond baseline healthcare benefits. Withum is proud to be at the forefront of exceptional benefits that support team members’ health journeys. In addition to its traditional medical, dental and vision plans, the Firm offers supplemental benefits. These include an…
Rochester Business Journal Names Withum Leaders on Accounting and Insurance 2026 Power List
Rich Wright Rich Wright is the Partner-in-Charge of Withum’s Buffalo, Rochester and Batavia offices, offering more than 30 years of public accounting experience and deep expertise in tax planning. He advises closely held businesses, high-net-worth individuals and business owners on complex tax compliance and advisory matters across multiple industries. A strategic, people-focused leader, Rich plays…
Forbes Names Thirteen Withum Leaders to Its Best-In-State CPAs List
Withum’s representation reflects the Firm’s collective power of people, reinforcing its position as a leading national advisory, tax and audit firm. From the East to the West Coast and representing a broad cross-section of services and industries, the Withum advisors listed reflect diverse expertise and leadership styles, united by a shared commitment to client and community service. Withum’s 2026 Best-In-State CPAs New Jersey New…
LA Times Names Two Withum Leaders on its Banking and Finance Visionaries List
About Aza Ghazaryan Aza Ghazaryan is a Tax Partner with over 20 years of experience serving as a trusted advisor to partnerships and high-net-worth individuals on tax planning and compliance. She advises clients across industries, including professional services, real estate, technology and not-for-profit. Aza has successfully guided clients and teams through complex regulatory changes, including the Tax Cuts and Jobs Act, federal…
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