We Work With You,
Not Just Your Numbers

If you are looking for that perfect balance between big firm expertise and small firm personal service, you just found it. 

We Are

We Are
Problem Solvers 

We Are Easy
to Work With
(Sometimes Even Fun) 

From large company structures to individuals – We will partner exactly to your level.

That is the big benefit to choosing MM & Company as your certified public accountants – Striking a comfortable balance between big firm knowledge and experience, and small firm exclusive, personal service. You can count on us to help you make sound business and tax decisions in a strategic manner from the beginning stages and continuing through to succession/estate planning.

Business meeting

Knowing you and your goals helps us provide the exact accounting services required to increase you and your business’ continued success.

Quick Info Guide

MM & Company provides a substantial array of accounting, tax and consulting services for corporate, business, personal & estate planning.

Browse our website. You will find articles, informational media links, self-guided tools, download-able tax forms and handy financial calculators to assist you straight from the site.

Click below to find more information on our most often asked-for services.


Southern California
& Orange County

Over 60 Years
of Combined

Wide Range of
Financial Services

MM & Company History

Henry Mendoza and Michelle McDuffie worked together for many years in Orange County before deciding to take the reins and start their own accounting firm—one that delivered big firm knowledge with small firm service, and with that, MM & Company was born. 

Because their commitment to professional excellence and “hands-on” approach resonated with many companies and individuals, their client list continued to grow, and MM & Company soon became the firm it is today. 

MM & Company strives to actually be “part of our client’s team” instead of just a vendor that provides a service. The company’s culture reflects that. With over 60 years of combined experience, they provide strategic expertise and mentorship that helps clients grow at a calculated pace while keeping them in compliance with ever-changing tax laws and accounting standards (domestic and foreign). Along with accounting, corporate and real estate structuring, MM & Company also provides financial audits, reviews, compilations and other attestation engagements along with fractional CFO advisory services. 

MM partners and staff alike always stay abreast of the latest tax regulations and accounting standards with advanced education and certification. 

As your trusted advisor, MM & Company understands that developing real relationships, building confidence and providing the clearest, most beneficial financial guidance is our common goal. That is who we are and will continue to be.

The MM & Company Executive Suite

The team at MM & Company was built on a solid relationship and has continued to grow. That solid relationship, complimentary skill and personal involvement is fundamental to our entire company and we want you to experience the same. Meet our dedicated management team.

Henry Mendoza, CPA

Mr. Mendoza has close to 40 years of experience as a Certified Public Accountant and is responsible for auditing services provided by the Firm including auditing and accounting related services, consulting, administration, marketing and recruiting. – READ MORE

Michelle McDuffie, CPA

Ms. McDuffie has over 25 years of experience meeting the needs of all types of businesses and providing innovative tax and business solutions to closely-held businesses with complex ownership structures READ MORE

Patrick Gibson, EA

Mr. Gibson has over 20 years of experience in public accounting, as well as five years’ experience in private industry. He specializes in corporate and limited liability company, multi-state and international tax structuring and tax planning READ MORE

Sissel Duesund, CPA

Ms. Duesund has over 15 years of experience in public accounting with experience in preparing, planning, compliance, and tax controversy work for a variety of business entities and individual tax returns. READ MORE

Brendan Martin, CPA

Mr. Martin has over 12 years of experience in public accounting with experience in leading financial statement audits, reviews, and compilations. Experience with not-for-profit organizations range from  READ MORE

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