What is a Certificate of Insurance (COI)?
A Certificate of Insurance is a one-page document that proves a business carries insurance. This guide explains what’s on a COI, how to read one, how to verify it’s valid, and what to do if you need to request or issue one.
What Does COI Stand For?
COI stands for Certificate of Insurance. It’s a one-page document, typically issued on the ACORD 25 form, that summarizes the insurance coverage a business carries. The rest of this guide explains what’s on a COI, how to read one, and how to verify it.
What is a Certificate of Insurance (COI)?
A Certificate of Insurance (COI) is a standardized document issued by an insurance broker or carrier that summarizes a business’s active insurance coverage. It tells the recipient three key things: who’s insured, what coverages they carry, and through what dates the coverage is active.
In the United States, almost every COI is issued on the same form: the ACORD 25. It’s a one-page summary, recognized industry-wide, that fits coverage details, named insureds, certificate holders, and policy dates onto a single sheet. When someone says “send me your COI,” they almost always mean send me your ACORD 25.
A COI is a summary, not the policy itself. The actual insurance policy is a multi-hundred-page contract with binding legal terms. The COI is informational. It exists so businesses can verify a vendor or contractor is insured without having to read the entire policy.
COIs are most common in industries where one company hires another to do work on its property or on its behalf: construction, real estate, transportation, events, professional services, and property management. In construction specifically, a general contractor will typically collect a COI from every subcontractor on every project before letting them on site.
What Is COI Insurance?
“COI insurance” is a slight misnomer — a Certificate of Insurance isn’t itself a type of insurance. It’s a document that proves a business already has insurance.
When someone asks about “COI insurance,” they’re usually asking one of three things:
Most COIs cover general liability, but a single certificate often summarizes several policies at once: general liability, workers’ compensation, auto liability, professional liability, umbrella, and any others the contract requires.
You need an active insurance policy from a licensed carrier. Once you have a policy, your broker can issue a COI summarizing the coverage on the standard ACORD 25 form.
When a company requests your COI, they’re verifying that the coverage on the certificate meets the requirements in your contract — limits, named insureds, additional insured endorsements, and so on. In construction, this verification is often automated through a COI tracking platform like Billy.
The short version: there’s no “COI insurance” you buy. You buy regular insurance, and the COI is the document that proves it.
How to Read a Certificate of Insurance
The ACORD 25 form is divided into clear sections. Reading a COI means knowing what to look at, in what order, and what specifically to check against your contract requirements.
1. Producer (top-left)
The Producer is the insurance broker or agency that issued the certificate. This is the contact you call if you need to verify the certificate is real, request changes, or follow up on a claim. The producer’s name, address, and phone number appear here.
2. Insured (top-right)
The Insured is the business that holds the policy. The name should match exactly what’s on your contract — including LLC, Inc., or DBA designations. A mismatch here is one of the most common reasons a COI gets rejected during compliance review.
3. Insurers Affording Coverage
This box lists the insurance carriers underwriting each policy. Each carrier is assigned a letter (A, B, C, D, E, F) that’s referenced later in the coverage section. Look for carriers with strong financial ratings — an A.M. Best rating of A− or better is the standard threshold most contracts require.
4. Coverages
The middle of the form is a grid showing each policy: type, policy number, effective and expiration dates, and coverage limits. Common coverages include:
- General Liability: Covers third-party bodily injury and property damage. Look for “Each Occurrence” and “General Aggregate” limits.
- Automobile Liability: Covers vehicles used for business. Verify the schedule (any auto, owned only, hired and non-owned, etc.).
- Umbrella / Excess Liability: Sits above the underlying policies for catastrophic claims.
- Workers’ Compensation: State-mandated coverage for employee injuries. Required if the vendor has employees.
- Professional Liability / E&O: Covers errors in professional services. Common for consultants, designers, and engineers.
5. Description of Operations / Locations / Vehicles
This section is where endorsement language appears. If you required additional insured status, waiver of subrogation, or primary and non-contributory wording, this is where the broker confirms it. The presence of an endorsement code (like CG 20 10) here references a specific endorsement attached to the policy.
6. Certificate Holder (bottom-left)
The Certificate Holder is the party requesting the certificate — the company that asked for proof of insurance. Their name and address must be exact. (Note: certificate holder is not the same as additional insured. Here’s the difference between certificate holder and additional insured.)
7. Authorized Representative
The signature line at the bottom right. A valid COI is signed by a licensed agent at the producer. Unsigned certificates are invalid.
Expired dates. Coverage that lapses before the project ends is non-compliant. Mismatched named insureds. The insured name must match the contract entity. Missing endorsements. If the contract required additional insured or waiver of subrogation, the description box should reference the endorsement — and ideally you should also collect the actual endorsement form. Low limits. A $1M general liability limit doesn’t help if the contract required $2M.
Common COI Endorsements
The COI summarizes coverage but doesn’t include the actual endorsement language. For high-stakes contracts, you should collect the endorsement forms in addition to the COI.
| Endorsement | Code | What It Does |
|---|---|---|
| Additional Insured – Ongoing Operations | CG 20 10 | Extends GL coverage to a third party (like a GC) during ongoing work on a project. |
| Additional Insured – Completed Operations | CG 20 37 | Extends GL coverage to a third party for claims arising after work is completed. |
| Waiver of Subrogation | CG 24 04 | Prevents the insurer from recovering claim payments from the additional insured. |
| Primary and Non-Contributory | Schedule wording | Specifies that the vendor’s policy pays first, before the additional insured’s own policy. |
Learn more about CG 20 10 additional insured endorsements and how they work in construction contracts.
How to Get a Certificate of Insurance (COI)
If someone has asked you for a COI, here’s how to get one in the next 24 hours:
- Contact your insurance broker. This is the fastest path. Email or call your broker, tell them who’s requesting the certificate, and pass along any specific requirements (additional insured, waiver of subrogation, specific limits).
- Provide the requesting party’s information. The broker will need the name and address of the certificate holder — usually the company asking you for the COI.
- Specify the requirements. If the requesting company sent you a contract or compliance form, attach it. Common requirements: minimum liability limits, named insured wording, additional insured endorsement (CG 20 10), and primary and non-contributory wording.
- Wait 24–48 hours. Most brokers issue COIs within one business day, free of charge, and can email the certificate directly to the certificate holder.
- Verify the issued COI matches the requirements. Before you send it, double-check that limits, endorsements, and named insureds match what was asked. A COI that doesn’t meet the requirements gets rejected and adds another round-trip to the timeline.
If you don’t have a broker, you can also request COIs directly from your insurance carrier through their online portal — though brokers are generally faster.
If you’re a subcontractor that has to provide COIs frequently, check whether the GC you work for uses Billy. Subs working with Billy-enabled GCs get a free Insurance Wallet to store and re-share their certificates, plus free tools like a W9 generator, lien waiver templates, and COI templates.
COI vs. Insurance Policy: What’s the Difference?
This trips up a lot of people, so it’s worth being explicit.
| Certificate of Insurance (COI) | Insurance Policy | |
|---|---|---|
| What it is | One-page summary document | Multi-hundred-page legal contract |
| Legally binding | No — informational only | Yes — it’s the contract |
| Issued by | Insurance broker or carrier | Insurance carrier |
| Cost to issue | Typically free | The policy premium |
| What it proves | That coverage exists, on what terms, through what dates | The actual coverage and its full terms |
| When you need each | For verification — sharing with vendors, GCs, landlords | For the underlying coverage and to confirm exact terms in a claim |
The practical implication: a COI alone is not enough to confirm exact coverage. For high-stakes contracts — large construction projects, professional services with big liability exposure — collect the underlying endorsement forms too. The COI tells you the coverage exists. The endorsements tell you what it actually covers.
How to Verify a COI Is Valid
Fake and altered COIs are a real fraud risk. The certificate is the easiest piece of insurance documentation to forge because it’s just a one-page form. Three steps to verify:
Don’t use the phone number or email printed on the certificate. Search the broker’s name on Google or check the state’s licensed insurance broker registry. Then call them directly to confirm the certificate.
Use AM Best (ambest.com) to verify the carrier exists and check their rating. A− or better is standard. Unrated or low-rated carriers are red flags.
For high-value contracts, request that the broker email you the certificate directly — not the vendor. Better yet, use a COI tracking platform that integrates with broker networks for real-time verification.
Frequently Asked Questions
What does COI stand for?
COI stands for Certificate of Insurance. It’s a one-page document, usually issued on the standard ACORD 25 form, that summarizes the insurance coverage a business carries.
What does COI mean in business?
In a business context, a COI is the document a vendor, contractor, or tenant provides to prove they carry adequate insurance. Companies request COIs from their vendors to verify coverage before entering into a contract or allowing work on a job site.
What is a COI in construction?
In construction, a COI is the certificate a general contractor collects from each subcontractor before they begin work on a project. It confirms the sub carries general liability, workers’ compensation, and any other coverages the contract requires — and that the GC is named as an additional insured.
What is a master COI?
A master COI is a single certificate that covers a vendor’s entire policy term, rather than being issued per project or per request. Vendors with frequent compliance needs sometimes use a master COI to reduce paperwork.
How do I get a COI?
You request a COI from your insurance broker or carrier. They issue it on the ACORD 25 form, typically free of charge, and can email it to you or directly to the party requesting it. Most COIs are issued within 24–48 hours.
What is the difference between a COI and an insurance policy?
The COI is a one-page summary of coverage. The actual policy is a multi-hundred-page contract that contains the binding terms. The COI is informational — it does not amend or extend coverage. To verify what’s actually covered, you need to review the underlying policy or specific endorsements.
Is a COI legally binding?
No. The COI itself is informational and is explicitly not a contract. The underlying insurance policy is the legally binding document. This is why best practice is to also collect specific endorsements (like CG 20 10 for additional insured status) rather than relying on the COI alone.
How long is a COI valid?
A COI is valid for the policy period it lists — typically one year. It expires when the underlying policy expires or is canceled. Most companies require vendors to provide a renewed COI before the prior one expires to maintain continuous compliance.
Can a COI be fake?
Yes. Fake or altered COIs are a real fraud risk. To verify a COI is legitimate, contact the issuing broker directly using contact info you look up independently — not the contact info printed on the certificate itself.
What is a COI form?
The standard COI form in the U.S. is the ACORD 25, a one-page document used industry-wide. Other ACORD forms exist for specific purposes (like ACORD 27 and 28 for property), but ACORD 25 is the COI form most people are referring to.
Related Reading
If you found this guide helpful, you’ll want these next:
- Best COI Tracking Software for Construction in 2026 →
- Certificate Holder vs. Additional Insured: What’s the Difference? →
- The CG 20 10 Additional Insured Endorsement Explained →
- CG 20 10, CG 20 37, and Primary & Non-Contributory Wording →
- 5 Essential Construction Compliance Documents to Track →
- Billy + Procore: Native COI Tracking Inside Procore →
- Free W-9 Generator →
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