What is a certificate of insurance?
A certificate of insurance (COI) is a one-page summary of an insurance policy, issued by the policyholder's insurance agent or broker, that shows what coverage exists at the moment of issue: the insured's name, the carriers, policy numbers, effective and expiration dates, and the key limits. In the U.S. it almost always arrives as an ACORD 25 form.
Businesses request COIs from vendors, subcontractors and tenants to confirm those parties carry their own insurance — so that when something goes wrong, the loss lands on the responsible party's policy instead of yours.
What a COI proves — and what it doesn't
A certificate is evidence, not a contract. The ACORD 25 says so itself: it 'confers no rights upon the certificate holder' and 'does not amend, extend or alter the coverage.' In practice that means three common traps:
- Coverage can be cancelled after the certificate is issued — the certificate doesn't update itself.
- The 'Additional Insured' checkbox is not the endorsement. The protection only exists if an endorsement (e.g. CG 20 10) is actually attached to the policy.
- Limits shown may be aggregate limits already eroded by other claims during the policy year.
How to verify a COI properly
A real verification checks four layers: (1) the certificate is current and the dates bracket your work; (2) the coverages and limits meet your contract's requirements; (3) the endorsements your contract names — additional insured, waiver of subrogation, primary & non-contributory — are attached as actual policy forms, not checkboxes; (4) renewals are re-verified when the policy period rolls.
Most teams do layer 1 in a spreadsheet and stop. Layers 2–4 are where claims are won and lost — and where software that reads the endorsement pages earns its keep.
Frequently asked questions
Who issues a certificate of insurance?
The insured party's insurance agent or broker issues it, usually on the ACORD 25 form, at the insured's request. You never issue a COI for someone else's coverage.
How long is a COI valid?
A certificate reflects coverage as of its issue date; the policies it summarizes each carry their own expiration dates (typically annual). Best practice is to re-collect certificates at every policy renewal.
Is a COI legally binding?
No. The certificate itself confers no rights and doesn't modify the policy. The policy and its endorsements are the binding documents — which is why verifying attached endorsements matters more than the certificate face.
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