Don Grimm, FCAS, MAAA, provides expert actuarial witness services with over 30 years of specialized experience in loss reserving and reinsurance. Don has successfully served as an expert witness in multiple high-stakes matters in recent years. He is a member of ARIAS-US (the AIDA Reinsurance and Insurance Arbitration Society), a leading nonprofit dedicated to improving the arbitration process in domestic and international insurance and reinsurance markets.
Representative Experience
United States v. James Douglas Miller, et al.
United States District Court, Western District of Washington
November 2021 – August 2023
Don served as an expert witness supporting the defense team led by Janet Hoffman & Associates in parallel criminal and SEC civil actions against the CFO of a publicly traded Professional Employer Organization (PEO). The case centered on allegations of financial fraud, with several charges relating to the management and reporting of loss reserves in the company’s large self-insured workers’ compensation program. Don provided expert analysis of the actuarial aspects of the reserves and delivered testimony in August 2023 before the U.S. District Court in Tacoma, Washington.
Reinsurance Arbitration (Confidential)
ARIAS-US Arbitration
July 2025 – November 2025
Don was retained by a major reinsurer, working in coordination with Mintz Law Firm, in an arbitration governed by ARIAS•US procedural rules. He provided expert analysis and interpretation of loss reserves, reinsurance contract provisions, and related actuarial issues. Don authored a detailed expert report, gave seven hours of on-the-record deposition testimony, and delivered both direct and cross-examination testimony at the hearing.
Reinsurance Dispute (Confidential)
Pre-Arbitration Engagement
January 2021 – February 2023
Don served as actuarial expert witness for Kennedy’s Law Firm in a reinsurance matter involving the interpretation of contract language as it relates to loss reserves and actuarial/accounting compliance. The case was successfully resolved through settlement prior to formal arbitration.
Don’s Cirriculum Vitae