Committee Members

Voting Members

Mark Wille Portrait
Mark Wille

CPA (2025)
AOC Chairman
Private Sector Member, 3rd District

Mark F. Wille earned his CPA in 1977 while employed by Arthur Andersen & Co. as an audit and tax accountant. He later joined one of the largest Southern California commercial real estate brokerage firms as vice president of finance.

In the mid 80’s, Mr. Wille started a private practice specializing in small business and real estate, providing professional services in financial, accounting and tax-related areas. He also worked on large public company purchases of small businesses.

Mr. Wille is a CPA firm peer reviewer for the American Institute of CPAs. He is former chair of the California State Accounting Principles and Auditing Standards Committee and a current member. He is former chair of the Audit Oversight Committee for the County of Orange, the sixth largest county in the United States. Mr. Wille teaches continuing education courses for CPA’s.

He has taught college business courses and frequently lectures to business and civic groups. On the personal side, he is an Eagle Scout and is active with the Orange County Boy Scout Council and served on a National Committee of the Boy Scouts of America. He has earned a master’s degree in theology from Fuller Theological Seminary.

His Newport Beach practice consists mainly of small business clients where he provides substantial strategic planning and financial coaching. Mark consults with CPAs regarding various accounting and auditing matters, provides practice management, peer review, and performs peer review inspections. He assists CPAs in the sale of their practices.

Stella Acosta Portrait
Stella Acosta

CPA (2023)
AOC Vice Chair
Private Sector Member, 4th District

Stella Acosta blends her deep subject-matter expertise and an engaging style with a governance perspective rarely found in auditing. For her, auditing is an art that she practices to help organizations improve their processes and, ultimately their performance. As a consummate problem-solver, Stella is the person to go to for a solution after others have failed.

Stella is the founder and principal consultant at Stella Acosta, CPA, Advisory & Assurance Services where she provides strategic guidance, an ethical and independent voice, and a healthy dose of skepticism in addressing issues related to the accuracy and reliability of operating, financial, and compliance information. Stella is an adjunct instructor of internal audit and control as well as financial accounting at California State University, Fullerton, where she is educating the next generation of accounting professionals.

Stella began her career as an IRS agent, and then rose within the internal audit profession to become the director of internal audit at two publicly traded companies, Motorcar Parts of America and Hines Horticulture. While at Hines, she was also responsible for Corporate Governance. While at Motorcar, she gained experience in global, multi-cultural environments. In both positions, Stella served under the direct oversight of the Board’s Audit Committee Chairperson, which enabled her to align internal audit with key governance and strategic initiatives. Stella executed customer and solution driven engagements using a consultative and partnership approach. She recommended proactive solutions on value-added and practical improvements to risk management and the effectiveness of operations, reporting, and compliance processes, including SOX, ICFR, ITGC and FCPA activities.

Stella’s board experience includes appointment as a voting private sector member on the County of Orange, California, Audit Oversight Committee, and elected secretary for The Institute of Internal Auditors, Orange County Chapter, Board of Directors. She received an MBA from the University of California, Irvine, and a BS in Accounting from San Diego State University. She is a Certified Public Accountant (CPA) and expects to receive the designation of Certified Internal Auditor in 2020. She is also a member of the Forum for Corporate Directors and has completed the Forum for Corporate Director’s Board Governance program.

Doug Chaffee Portrait
Doug Chaffee

Board Chairman
Supervisor, 4th District

Donald P. Wagner Portrait
Donald P. Wagner

Board Vice Chairman
Supervisor, 3rd District

Frank Kim Portrait
Frank Kim

County Executive Officer

Drew Atwater Portrait
Drew Atwater

Private Sector Member, 1st District

Drew Atwater is the Director of Finance and Water Resources at Moulton Niguel Water District, overseeing the finance, water efficiency, and water resource planning departments. Drew has overseen the integration of District analytical talent across disciplines to create an interdisciplinary data science and quantitative team to improve efficiencies throughout the agency. Mr. Atwater has a Bachelor of Arts in Physics from Reed College and a Masters in Science in Environmental Science focusing in Environmental Economics and Policy from the University of California at Riverside.

Yvonne Rowden

Private Sector Member, 2nd District

Bob Brown Portrait
Robert Brown

Private Sector Member, 5th District

Bob Brown was appointed to the Orange County Audit Oversight Committee in 2016 to serve as Fifth District Supervisor Lisa Bartlett’s representative. Bob previously served 14 years on the Laguna Niguel Investment, Banking & Audit Committee, including three terms as chair.  He is a current member and past chair of the Laguna Niguel Planning Commission and is past president of the 500 member Orange County Financial Planning Association.  Bob is a CERTIFIED FINANCIAL PLANNER™ (CFP®) professional and holds the Chartered Life Underwriter (CLU) and Chartered Financial Consultant (ChFC) professional designations. 

Bob was educated by the Benedictines at St. John’s University, Collegeville, MN before graduating from the University of Minnesota, Carlson School of Business, with a B.S. in Business Administration.  He is a member of the Laguna Niguel Chamber of Commerce and the Laguna Niguel Rotary Club.

Non-Voting Members

Frank Davies
Shari Freidenrich Portrait
Shari Freidenrich
Agripino Alonso Portrait
Aggie Alonso

Director of Internal Audit