Introducing Our Team

Accountants and advisors to Silicon Valley since 1979.

Byron Ishiwata, CPA

Tax Partner
Johanson & Yau

Review my background on FINRA’s BrokerCheck

Byron Ishiwata, CPA

Business Consulting
Estate Planning
Financial Statements
International Tax
Mergers & Acquisitions
Personal Financial Planning
Small Business Accounting
Succession Planning
Tax Authority Examinations
Tax Planning & Return Preparation


Professional Services
Real Estate


FINRA Series 7 & 66
California Insurance License #0E32247
Certified Public Accountant (CPA)


American Institute of Certified Public Accountants (AICPA)
California Society of Certified Public Accountants (CalCPA)


Japanese-American Chamber of Commerce
Konko Church of San Jose, Head Minister
Japanese American Museum of San Jose, Board Member


Bachelor of Science – Commerce, Santa Clara University
Master of Business Administration – Taxation, Golden Gate University

“Personal service sets us apart.”

I joined Johanson & Yau in 1983 and became a partner in 2002. I specialize in serving individuals, corporations, partnerships and estates and trusts. I take great pride in personal service and enjoy helping clients meet their goals.

I’m avid sports fan and hold season tickets for all of the major teams in the Bay Area. I also serve as the assistant chief administrative minister for the Konko Churches of North America. I was born and raised in San Jose.


Avantax affiliated advisors may only conduct business with residents of the states for which they are properly registered.  Please note that not all of the investments and services mentioned are available in every state.

Securities offered through Avantax Investment ServicesSM, Member FINRA, SIPC. Investment advisory services offered through Avantax Advisory ServicesSM. Placing business through Avantax Insurance AgencySM and Avantax Insurance ServicesSM. David R. Davis, CPA/PFS – CA Insurance #0E01220. Byron Ishiwata, CPA – CA Insurance #0E32247. Elier Peraza, CFP® – CA Insurance #0K42603

The Avantax family of companies exclusively provide investment products and services through its representatives. Although Avantax Wealth ManagementSM does not provide tax or legal advice, or supervise tax, accounting or legal services, Avantax representatives may offer these services through their independent outside business. This information is not intended as tax or legal advice. Please consult legal or tax professionals for specific information regarding your individual situation.

Content, links, and some material within this website may have been created by a third party for use by an Avantax affiliated representative. This content is for educational and informational purposes only and does not represent the views and opinions of Avantax Wealth ManagementSM or its subsidiaries. Avantax Wealth ManagementSM is not responsible for and does not control, adopt, or endorse any content contained on any third-party website.