Mr. Greenberg is an attorney and well respected financial planner, and the founding principal of Wealth & Tax Planners (WTP). He specializes in retirement and estate planning, elder care issues, insurance cost reduction, portfolio construction, and management. He helps clients save on taxes and reduce the risk to one's principal.

Among his clientele are retired physicians, business executives, teachers, and widows alike. His plans have helped clients cut their taxes significantly, saving on income, capital gains, and estate taxes.

Mark's "Successful Retirement Planning" classes, taught at CalState and JFK University in Walnut Creek, Pleasant Hill, and San Ramon, have been widely attended by employees and executives of Chevron, PacBell, GE, and UC Berkeley. He contributed to a book (published June 2005), "Achieve Retirement and Education Security", part of the Living & Learning series of "Practical Answers from America's Foremost Financial Advisors". He was also co-editor of "Wealth  & Tax Strategies", a quarterly newsletter of financial advice to upper income clients. 

Mark's professional designations include being an Investment Advisory Representative with Wealth & Tax Planners. He is a Certified Financial Planner™ (CFP®), passing exams in investments, insurance, taxation, retirement, and estate planning. He is also licensed by the State of California Dept. of Insurance (#0675661). He received his Juris Doctorate law degree from Benjamin Cardozo School of Law in New York while attending on scholarship, and his BA Cum Laude from the State University of New York.

Prior to beginning his financial advisory practice, Mark practiced law in Oregon, and then Oakland, CA from 1982 - 84, focusing on real estate and corporate law. Mark was appointed as a Director for the City of Portland (1981), having regulatory and fiscal responsibility over the local cable companies.

When not helping people achieve wealth and save taxes, Mark enjoys skiing, music (plays in a band!), travel adventures, and especially helping his daughter make her way in the world. Some of his fondest memories are of volunteering at her school, and helping teach computers to the class. Mark has raised funds for The Wounded Warrior Project, Multiple Sclerosis Society, and Putnam House for the  mentally handicapped and their families, and other charities. He served on the Board of Directors of his 200 member ski-social club, and has been Past President.

Thomas W. Sepull, MBA

Senior Financial Advisor & Chief Strategist

Tom is a Senior Financial Advisor and Chief Strategist with Wealth & Tax Planners, bringing over 30 years of experience in global markets, financial planning, and risk management. His career began with 11 years at Montgomery Securities in San Francisco, where he advised institutional clients across Asia, including Japan, Hong Kong, Singapore, Malaysia and Australia. Tom later held senior roles at Banc of America Securities and the Royal Bank of Canada before shifting his focus to comprehensive financial planning and wealth management.

As a Registered Investment Advisor (RIA), Tom upholds a fiduciary duty—meaning he is legally bound to act in his clients’ best interests and provide investment advice that is objective, transparent, and tailored to their goals. He is also deeply involved in tax planning strategies, helping clients reduce liabilities, optimize cash flow, and integrate tax efficiency into their broader investment and estate plans. With over 16 years of experience using advanced cash flow management software such as eMoney, Tom develops detailed retirement and financial models that help clients visualize, plan, and successfully achieve their long-term goals.

Tom holds a BA from the University of California, Santa Barbara and an MBA from St. Mary’s College of California. In addition to his advisory role, he is an independent insurance broker (CA Insurance License #0F45482), helping clients obtain or restructure life insurance to reduce costs, increase benefits, and align coverage with evolving financial goals. He is licensed with Series 7, 63, and 66 registrations, and has extensive expertise in portfolio risk-reduction strategies, retirement income planning, and tax-efficient wealth transfer.

A seasoned entrepreneur, Tom has founded and led businesses in both technology and medical services, giving him a deep understanding of small business operations and executive decision-making. 

With a truly global perspective, he brings four years of international experience in Japan, where he worked across business development, technology, and education. His passion for cultural exchange runs deep—shaped early by spending his junior year of high school abroad in Prüm, Germany—and continues today through lifelong global travel and connection. Married to a native of Australia and still closely connected with colleagues and friends throughout Asia and Europe, he brings a unique international background that enriches his ability to understand diverse perspectives and deliver forward-thinking solutions.

Tom is also active in community service and leadership. He served as Founder and Facilitator of Men Creating Peace, a 501(c)(3) non-profit based in Oakland that helps men build greater awareness around domestic violence issues and positive behavioral change. He also founded The Fathers Circle, a support organization dedicated to helping men raising children with special health care needs and developmental disabilities. These experiences reflect his deep commitment to personal growth, empathy, and service to others—values he brings to his advisory practice every day.

Outside of work, Tom enjoys time traveling with his wife and children, soccer, basketball, surfing, backpacking, and golf. He is proficient in German and Japanese, and lives in Walnut Creek with his wife and their three children.

Karen, without whom our work would not be possible, runs the Wealth & Tax Planners office like a tight ship. As Operations Manager for over 14 years, she is the central point of contact for all administrative and client service matters—handling everything from required minimum distributions (RMDs), investment additions, and regular withdrawals to account access, tax forms, beneficiary updates, and countless other client needs with precision and care.

A native of Australia, Karen has called the Walnut Creek area home for over two decades. She brings warmth, professionalism, and a personal touch to every client interaction—ensuring that each person who calls or visits feels welcomed and well cared for.

Outside the office, Karen is married and the proud mother of two successful children. She has a lifelong passion for horses and animals of all kinds and is also an avid traveler and global cruise enthusiast, always planning her next adventure on the open seas.