Tax Services
Orange County, CA
Located in the heart of Irvine’s business district, Withum is one of the nation’s top-rated and largest accounting firms in Orange County.
Withum helps local corporations and nonprofits thrive, offering advisory, tax, audit, assurance and consulting services to the Orange County business community. We are more than just an Irvine accounting firm, we are a strong national resource providing all the traditional CPA and accounting services businesses and individuals require, plus a whole suite of advisory solutions to accelerate your success. That’s the Power in the Plus!
(949) 261 2808
Orange County Service Specializations
Assurance and Accounting
Employee Benefit Plan Audits
Outsourced Accounting Systems and Services
Public Company SEC Compliance & Reporting
Transaction Advisory
CA State and Local Tax Updates
Do you or your organization operate in multiple states? Do you own property in a variety of states? California 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 California 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 Orange County
Beyond the Region
- Inside Public Accounting Top 100 Firms – 23rd 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
Kenneth L. Johnson, CPAKen is the Partner-in-Charge (PIC) of the firm’s Orange County office. Ken brings nearly three decades of expertise in conducting audits and reviews for both privately held and publicly traded companies.
In addition to his successful career working with and advising the firm’s clients, Ken dedicates much of his time to non-client-focused activities, such as the daily operations and people strategy of the Orange County office and its growth in the local marketplace. He is passionate about mentoring the next generation and providing them with the same opportunities he had. Ken is helping the younger team members grow the firm and contribute to this office’s legacy of entrepreneurship. By acting as a business owner first, he is setting an example to the office of the advisory experience we should bring to our clients, above and beyond the compliance work of audits and tax.
Orange County Leadership
Withum in the News
Sameer Uddin Named to Caseware’s 2026 30 Under 30
Advancing Audit Innovation Sameer has played a key role in advancing Withum’s use of audit technology, helping teams adopt new methodologies, improve efficiency and enhance consistency across engagements. A trusted resource for technology implementation, he has been instrumental in the Firm’s adoption of Caseware Cloud and Dynamic Assurance Solutions (DAS) applications. Driving Firmwide DAS Adoption…
Withum Team Members Named as INNOVATE100 Honorees
Leading Industry with a Tech–Forward Vision Matt Walsh, partner and practice leader of Withum’s Industrial and Consumer Products Services Team, was honored in the Finance/Accounting category for helping modernize the Firm’s technology ecosystem. His leadership has supported initiatives that enhance efficiency, streamline workflows and better align technology with evolving client needs, including work with Caseware…
Alan Iosue Named 2026 LA Times Entertainment Business Visionary
As a trusted advisor to entertainment clients, Alan helps organizations navigate the unique opportunities and complexities of an increasingly dynamic, deadline-driven industry. This recognition reflects his commitment to delivering strategic guidance that supports both immediate business needs and long-term success across Southern California’s creative economy. Alan advises production companies, professional athletes, arts organizations and closely…
Withum Ranked a Top 20 Firm Among 2026 IPA 100 Firms
The annual IPA 500 ranks the 500 largest accounting firms in the United States by net revenue using data submitted through the IPA Practice Management Survey. A Growth Strategy Guided by The Withum Way Withum’s rise into the Top 20 reflects purposeful investment. As an independent, owner-operated firm, Withum has the flexibility to make long-term investments that support sustainable growth while maintaining its culture and deepening client relationships. Innovation…
Robin Kim Joins Withum Capital as Managing Director of Investment Banking
Robin brings more than 20 years of investment banking and principal investing experience, advising founder-led, family-owned and privately held companies. Throughout his career, he has advised on transactions exceeding $30 billion in aggregate value, including M&A transactions, leveraged buyouts, recapitalizations, restructurings and debt and equity financings. His experience spans a broad range of industries, providing…
Contact Us
We will make every attempt to respond to your inquiry in a timely manner.