Certificate of Insurance (COI): What It Is & How It Works

The short answer (as of July 2026)

A certificate of insurance (COI) is a one-page summary of your insurance coverage — the insurance company, policy numbers, coverage types, limits, and effective dates — issued as proof of coverage for a customer, landlord, or lender. It is not the policy itself and it does not change your coverage; it simply shows a third party that the coverage exists. Your broker issues it, usually the same day you ask.

What a Certificate of Insurance Actually Is

A COI is evidence, not coverage. In the U.S., most certificates are issued on a standardized industry form (the ACORD 25 for liability coverage), which is why every COI you see looks nearly identical: named insured at the top, a grid of coverage types with limits and policy dates in the middle, and the certificate holder — the party that requested proof — at the bottom.

Three things a COI does not do:

• It does not create, extend, or amend coverage. Only the policy and its endorsements do that. The fine print on the form says so explicitly.
• It does not guarantee the policy stays in force. Coverage can be cancelled after a certificate is issued, which is why some contracts also ask for notice-of-cancellation provisions.
• It does not make the certificate holder an insured. Being listed as certificate holder just means you receive the form; additional insured status is a separate endorsement on the policy itself.

Who Asks for a COI — and Why

Almost every business relationship that involves risk transfer eventually involves a certificate:

• Enterprise customers. The insurance clause in a master service agreement typically requires specific cyber and tech E&O coverage and limits for software vendors, plus a certificate delivered before signature or renewal. See our guide to enterprise contract insurance requirements.
• Landlords. Office and warehouse leases commonly require general liability at limits specified in the lease, with the landlord named as additional insured and the coverage evidenced by a COI before you get keys.
• Lenders and investors. Loan covenants and some financing documents require proof of coverage as a closing condition.
• Vendor and partner onboarding. Marketplaces, general contractors, event venues, and channel partners routinely collect certificates from every vendor as a matter of policy.

The pattern is the same in each case: the requesting party wants to know that if something goes wrong, there's an insurance policy — not just your balance sheet — standing behind the obligation.

How to Read a COI: The Boxes That Matter

When a certificate lands in your inbox — yours or a vendor's — these are the fields worth checking:

• Named insured. Must exactly match the legal entity signing the contract. A certificate for "Acme Labs LLC" doesn't prove anything about "Acme Labs, Inc."
• Insurer and rating. The carrier for each line of coverage. Sophisticated counterparties often require carriers rated A- or better by AM Best.
• Policy period. Effective and expiration dates. A certificate showing coverage that expires mid-contract will usually generate a renewal-time follow-up request.
• Limits. Per-occurrence and aggregate limits for each coverage line. This is the box procurement compares against the contract's insurance clause.
• Description of operations. Where special language lives — additional insured status, waiver of subrogation, primary and non-contributory wording. If the contract requires these, they should be referenced here and actually endorsed onto the policy.
• Certificate holder. The party the certificate was issued to. Remember: holder status alone confers no coverage rights.

Additional Insured vs. Certificate Holder

This is the distinction that trips up the most contracts. A certificate holder simply receives proof of your insurance. An additional insured is actually added to your policy by endorsement, gaining rights under it — most importantly, the right to defense and coverage if they're dragged into a claim arising from your work.

Many leases and MSAs require additional insured status, not just a certificate. Whether that costs anything depends on the policy: many general liability and tech E&O forms include blanket additional-insured endorsements that apply automatically where a written contract requires it, while others need a specific endorsement added. Ask your broker before you promise it in a contract — and never assume that being listed on the certificate alone satisfies the requirement.

How Fast Can You Get a COI?

If your coverage is already in place and the request is standard — a certificate naming a landlord or customer, with common additional-insured wording — a broker can typically issue it the same business day, often within hours. What slows things down is when the contract demands coverage you don't actually carry: higher limits, a coverage line you skipped, or endorsement wording your current policy can't support. Then the certificate request becomes a mid-deal insurance purchase, under deadline pressure.

The practical advice: send your broker the insurance clause of any significant contract before you sign it. Confirming your program satisfies the requirements takes minutes; discovering a gap after signature costs days. OnePark Risk clients get named response windows on certificate requests, because we know a slow cert is a stalled deal.

Sources

• Certificate of Insurance — International Risk Management Institute (IRMI)
• Guide to Best's Credit Ratings — AM Best