Certificate of Insurance (COI)
A one-page document that evidences the existence, type, limits, and effective dates of insurance policies. Issued by the insured's broker or carrier to project owners, general contractors, and other parties who require proof of coverage.
A certificate of insurance, or COI, is a standardized document that evidences the existence and terms of insurance policies. It is the primary way contractors prove coverage to owners, GCs, and regulators before starting a job.
What the Certificate Shows
The standard ACORD 25 certificate lists the insured's name and address, each policy in force with its type, policy number, limits, and effective dates, and the certificate holder who is receiving the document. Additional insured status and waiver of subrogation can be noted on the certificate, and endorsement numbers can be referenced in the description section.
What It Does Not Do
The certificate is evidence of insurance. It is not a contract. It does not modify the policy. It does not create coverage that does not exist in the underlying policy. A certificate that says "General Contractor is named as additional insured" means nothing unless there is a corresponding AI endorsement on the policy. Owners requiring AI status should demand both the certificate and the underlying endorsement.
How to Use COIs Well
Contractors maintain a file of COIs from every subcontractor and supplier they use, updated at each policy renewal. Owners and GCs require COIs before work begins and often at renewal. Best practice is to also require notice of cancellation so the certificate holder is told if coverage lapses mid-project. Some jurisdictions also require specific language about the insured's workers comp and auto coverage to satisfy contractor licensing requirements.
Frequently asked questions
A COI lists the insured's name, the policy types in force (general liability, auto, workers comp, etc.), the policy numbers, effective dates, limits, and the certificate holder. If special endorsements apply (additional insured, waiver of subrogation), those are noted in the description section or on an attachment.
No. The certificate is evidence that coverage exists; it does not itself create coverage. The actual coverage and endorsements are in the underlying policy. A certificate that lists someone as an additional insured without a matching endorsement in the policy does not deliver actual AI coverage.
Call the broker or agent listed on the certificate and confirm the policies are in force. Request copies of the endorsement forms referenced on the COI (for AI and waiver of subrogation). Do not rely on a certificate alone for major contracts; the endorsements are what matter.
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