Mike Grant

Michael Grant
Principal, CPA


Mike is a principal of Costello & Sons Insurance (CSI), a Property & Casualty Insurance Brokerage that currently writes approximately $40 million in insurance premiums. As a sixteen-year veteran of the insurance industry, Mike’s expertise is in the design of custom risk management programs for Technology companies and REALTORS®.

Prior to entering the insurance industry, Mike held a number of positions within the accounting and finance area. These positions included the Chief Financial Officer position for an environmental consulting firm, Senior Auditor for Ernst & Young and Postgraduate Technical Assistant at the Financial Accounting Standards Board. During this period, he attained the Certified Public Accountant (CPA) designation in California.


  • Accredited Advisor In Insurance (AAI) designation
  • Past President – Ernst & Young Alumni Association
  • Board of Directors – Olive Crest
  • Advisory Board Member – Keynote

BA, Business Administration, Albion College, 1987
Insurance Licenses and Designations
Property & Casualty (since 1994)
Certified Public Accountant

Mike and his wife of 14 years, Sandra, have three children, Jacob, Jessie and Bailey who all reside in Santa Ana, CA. Mike is active in working with the youth of his local community, volunteering at a number of charities and a variety of sporting activities.



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