What a certificate of insurance actually proves
A certificate of insurance — a COI — is a one-page summary of somebody else's insurance policy. When you hire a subcontractor, you ask for their COI so you have evidence they carry coverage. Almost every one you receive will be an ACORD 25, the industry-standard form.
Here is the part worth understanding before you rely on one: a certificate is a snapshot, not a guarantee. It says a policy existed on the day the certificate was issued. It is not the policy, it does not modify the policy, and it does not promise the policy is still in force today. The form says so itself, in the small print at the top.
How to read an ACORD 25
Working down the form, these are the fields that matter to a general contractor:
| Section | What it tells you |
|---|---|
| Producer | The insurance agency that issued the certificate. Your point of contact if something looks wrong. |
| Insured | The subcontractor's legal business name. Check it matches the entity on your contract — "Vega Plumbing LLC" and "Vega Plumbing & Heating Inc" are different companies, and only one of them is covered. |
| Insurer(s) Affording Coverage | The carriers, each with a NAIC number. Several policies from several carriers can appear on one certificate. |
| Type of Insurance | General liability, auto, umbrella, workers' compensation. Each line is a separate policy with its own dates. |
| Policy Eff / Policy Exp | Effective and expiration dates. This is the field that matters most, and the one everything in SubCover is built around. Each line has its own — they frequently differ. |
| Limits | The maximum the policy pays. Compare against what your contract requires — a certificate showing $500,000 when you specified $1,000,000 is a problem, not a formality. |
| Certificate Holder | Who the certificate was issued to. It should be your company. One made out to somebody else tells you nothing about your relationship with that sub. |
| Description of Operations | The free-text box. Additional insured status and waivers of subrogation usually get noted here, and it is the least standardised part of the form. |
The four coverages you will see most
- Commercial general liability (CGL) — third-party bodily injury and property damage. The one people mean when they say "are they insured?"
- Workers' compensation — injuries to the sub's own employees. In most US states this is compulsory, and if a sub has no coverage their injured employee's claim can land on your policy.
- Commercial auto — vehicles. Relevant whenever a sub drives to your site, which is always.
- Umbrella or excess — additional limits above the policies underneath. Beware of reading an umbrella's long expiration date as evidence of coverage: it sits on top of the primary policy and does very little once that has lapsed.
What a certificate does not do
- It does not keep the policy in force. A sub can cancel the day after the certificate is issued and your copy will look exactly the same.
- It does not make you an additional insured. That comes from an endorsement on the actual policy. A note in the description box is a claim that one exists, not the endorsement itself.
- It does not guarantee you will be told about cancellation. The cancellation clause obliges the insurer to follow the policy's own terms, which may mean notifying the policyholder — your sub — and not you.
- It does not confirm the coverage fits your job. Exclusions live in the policy. A residential exclusion on a policy for a subcontractor working on houses is not visible on the certificate.
What this means in practice
Because a certificate only proves what was true on its issue date, the discipline that matters is tracking expiration dates and collecting a fresh certificate every renewal. That is unglamorous and it is where most small contractors lose the thread — not because they do not care, but because it means remembering fifteen different dates and chasing fifteen busy people.
If a certificate has already lapsed, the practical steps are in what to do when a sub's COI has expired. If you need to ask for one, there are templates in how to request a COI.
SubCover is a record-keeping tool, not an insurance product, and none of this is insurance advice. Whether a specific certificate satisfies a specific contract is a question for your agent or attorney.