Definition
A certificate of insurance (COI) is a short document, usually on a standard industry form, that summarizes a company's insurance: carriers, policy numbers, coverage types, limits and dates. Businesses ask staffing agencies for a COI showing general liability and workers' compensation before crews arrive, and venues or general contractors often need to be listed as certificate holder or additional insured. A COI is proof of coverage on the day it is issued, so many clients request an updated one at renewal.
This definition is general information, not legal, tax or financial advice. Rules vary by state and change over time.