What Is a Certificate of Insurance (COI) and When Do You Need One?

A certificate of insurance (COI) is a one-page snapshot that summarizes your insurance policies, the carriers, policy numbers, coverage types, limits, and effective dates, issued as evidence that coverage exists on the date the certificate was produced. You'll need one whenever a landlord, general contractor, or client requires proof of coverage before doing business. It is informational only: a COI does not change your policy, does not create coverage, and by itself does not make the certificate holder an additional insured. Only the policy and its endorsements do that.

That distinction between a certificate holder and an additional insured is the single most misunderstood thing in commercial insurance, and it trips up landlords, general contractors, and small businesses every day. Here's how certificates actually work.

Certificate of Insurance (COI)

A certificate of insurance is a one-page document summarizing a business's insurance policies, issued as evidence that coverage existed on the date it was produced. It is informational only: it does not change the policy, create coverage, or by itself make the holder an additional insured.

What is a certificate of insurance?

A certificate of insurance is a standardized summary document, the ACORD 25 form is the common industry standard for liability coverage, that your insurance agent or broker issues to a third party (the "certificate holder") who wants proof that you carry insurance. It typically shows:

• The named insured (you) and the issuing agency
• Each insurer providing coverage
• Policy types (general liability, auto, workers compensation, umbrella), policy numbers, and effective/expiration dates
• Limits of insurance for each coverage
• A description of operations, and the certificate holder's name and address

Requesting and issuing certificates is one of the highest-volume service tasks in any brokerage, contractors and subcontractors request them constantly, which is why many agencies offer COI self-service through online portals. That volume is exactly why it's worth understanding what the document does and doesn't do. A COI never confers coverage. It is evidence that policies existed on the day it was issued, it does not amend the policy, create rights for the holder, or make anyone an additional insured. When the certificate and the policy disagree, the policy wins.

When do you need a certificate of insurance?

Any time another party wants proof you're insured before doing business with you. The most common triggers:

On the flip side, you should be collecting certificates from every subcontractor and vendor who works for you, hiring uninsured help can leave you holding their claims.

Does a certificate of insurance make someone an additional insured?

No, and this is where real money gets lost. Under the standard ISO CGL policy, additional insured status must be granted by endorsement to the policy. The certificate merely reports what the policy says, it cannot add to it. If a contract requires that a landlord or general contractor be an additional insured, three things have to line up:

1. The contract states the requirement.
2. The policy is endorsed with a scheduled or blanket additional insured endorsement.
3. The certificate then accurately reflects the endorsement.

A certificate that claims additional insured status the policy doesn't actually grant protects no one, the certificate holder has a piece of paper, not coverage.

Why does additional insured status matter enough to insist on the endorsement? Because it delivers real benefits a certificate can't:

• Direct rights under the other party's policy: including defense costs paid as supplementary payments outside the limits, when the insured's duties are met
• A backup if a hold harmless agreement fails: for instance, when an anti-indemnity statute invalidates the contractual indemnity
• Protection from the insurer's subrogation: carriers generally don't pursue their own insureds
• Access to the named insured's limits: on top of your own coverage

What else do contracts ask for alongside a COI?

A certificate request is usually the visible tip of a set of contractual insurance requirements. The common bundle:

• Additional insured status: as above, endorsement required.
• Waiver of subrogation: the insured agrees its insurer won't recover a paid loss from the other party. The CGL permits a pre-loss waiver, but parties often want it documented by endorsement. The workers comp policy requires the WC 00 03 13 endorsement, and some states prohibit the waiver entirely.
• Primary and noncontributory wording, the named insured's policy pays first, without seeking contribution from the additional insured's own insurance.
• Notice of cancellation or nonrenewal: contracts increasingly ask that the certificate holder be notified of changes, sometimes of any change, which requires carrier cooperation and can be cumbersome to honor.

Each item on that list is a policy matter. The certificate is just where the results get reported.

How to request, issue, and track COIs the right way

A clean certificate process comes down to four habits:

• Pull the insurance requirements out of the contract early: ideally before you sign. Clients often agree to insurance clauses without consulting their broker, then discover the policy can't deliver what the contract promised.
• Match every requirement to a policy mechanism: additional insured, waiver of subrogation, primary and noncontributory, notice provisions, confirm each is available on your policy and get the endorsements issued.
• Issue the certificate to reflect reality: the COI should mirror what the policy actually says. A certificate that overstates coverage helps no one and creates E&O exposure for the issuing agency.
• Collect and diary certificates from parties working for you: track expiration dates and re-request at renewal. A certificate proves coverage existed on the day it was issued, policies can cancel afterward, which is exactly why holders ask for notice-of-cancellation provisions.

When reviewing a subcontractor's COI, check more than the limits: confirm the policy period covers your project dates, the coverage types match the contract (see what general liability covers), and, for claims-made lines, understand how the trigger works. Our guide to occurrence vs. claims-made policies explains why that matters.

This guide is for educational purposes and summarizes standard ISO policy language. Your policy's specific terms, conditions, and endorsements control. Talk to a licensed broker about your actual exposures.