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 – 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
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
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…
Withum Names Eighteen New Partners
Introducing Our 18 New Partners
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…
Withum’s Columbia Office Welcomes Greater Baltimore
Withum team members, clients and community leaders, including representatives from Howard County and the Central Maryland Chamber, came together to mark the official “door opening” on the new location. The ribbon-cutting ceremony highlighted the evening, which featured citations presented by community leaders welcoming Withum to the Columbia region and recognizing its strong ties to the…
Nadia Matthie Appointed as Chair of the AICPA’s Employee Benefit Plans Expert Panel
The AICPA’s Employee Benefit Plans Expert Panel was formed to protect the public interest and agree on key plan issues by leveraging the knowledge of leaders in the employee benefit plan industry. Nadia’s deep expertise makes her a valuable asset to help further the panel’s mission as Chair of the group. Nadia has more than…
Contact Us
We will make every attempt to respond to your inquiry in a timely manner.