What is a certificate of insurance?

A certificate of insurance (COI) is a one-page document proving a business has active insurance. It summarizes the carrier, policy numbers, coverage types and limits, and effective dates (usually on an ACORD 25 form) and is issued to a client, landlord, or partner as proof of coverage. It isn't the policy itself and doesn't change the coverage the policy provides.

What is the purpose of a certificate of insurance?

Its purpose is to give a third party (a client, landlord, or general contractor) quick, shareable proof that a business holds the required coverage before work begins or a lease starts. It transfers financial risk to the contractor's insurer if their work causes injury or property damage, without exposing the full policy contract.

Where do I get a certificate of insurance?

Request a COI from your insurance agent, broker, or carrier. Many providers let you generate one from your online account, often free of charge. Tell them who the certificate holder is and any coverage or additional-insured requirements from the contract, so the certificate matches what the requesting party asked for.

What does "additional insured" mean on a COI?

Being named as additional insured means the certificate holder gets coverage under the policyholder's policy for claims arising from the insured's work. A client often requires this so they're protected if the contractor's work causes a loss. It's stronger protection than simply being listed as the certificate holder.

How long should I keep certificates of insurance?

Keep each COI at least as long as the contract or relationship it covers, plus the statute of limitations on related claims, commonly three to six years. If a vendor's work later causes a loss, the COI on file proves they were insured at the time, which is exactly when you'll need it.

Insurance

Certificate of Insurance (COI)

A Certificate of Insurance (COI) is a one-page document, issued by an insurer or broker, that proves a business carries active insurance. It summarizes the carrier, policy numbers, coverage types and limits, and effective dates (most often on a standardized ACORD 25 form) and is issued to a client, landlord, or partner as proof of coverage. The COI is informational only: it does not amend, extend, or alter the underlying policy.

Under New York Insurance Law § 502, a certificate of insurance cannot amend, extend, or alter the coverage provided by the policy it references. It is evidence of coverage only.

Source: NY DFS: Certificates of Insurance

Written & maintained by the Granite team · Last updated October 2026

Overview

A COI is issued by an insurer or broker at the policyholder's request, usually to satisfy a contract requirement. A client won't let work begin, or a landlord won't hand over keys, until they hold a current COI naming the right coverages and limits, and often naming them as an "additional insured."

The COI is not the policy itself; it's a snapshot that proves coverage exists as of its issue date and confers no rights beyond what the policy already grants. Because it expires when the underlying policy renews, businesses end up re-issuing and collecting COIs constantly.

When you’ll get your Certificate of Insurance (COI)

A client or general contractor requires proof of coverage before you start work
A landlord requires a COI before a commercial lease begins
You're a vendor and a partner needs you on file as insured
You requested one from your broker to meet a contract clause
You collect COIs from subcontractors to confirm they're covered

What’s on your Certificate of Insurance (COI)

These are the fields you’ll find on one, and what each one tells you.

Insured: The business that holds the policy the certificate describes.
Certificate Holder: The party the COI is issued to: the client, landlord, or partner requiring proof.
Coverage Types & Limits: The policies summarized (general liability, auto, workers' comp) with their limits.
Policy Numbers: The identifiers for each underlying policy the certificate references.
Effective & Expiration Dates: The window during which the underlying coverage is active.
Additional Insured: Whether the certificate holder is named as additional insured on the policy.

How long to keep it

While active + 6y

Keep while it's active, then 6 years

If a subcontractor's work causes a loss after the project ends, the COI on file proves they were insured at the time, but only if you kept it. Discarding COIs at project close removes your evidence exactly when a late claim needs it.

This is general guidance.

How Granite handles your Certificate of Insurance (COI)

Granite reads each COI on upload (the insured, certificate holder, coverage limits, policy numbers, and expiration date) and files it in your Certificate of Insurance collection. When a subcontractor's certificate is about to expire, it can flag it before you've got an uninsured party on site, instead of finding out after a loss.

FAQ

Certificate of Insurance (COI): common questions

What is a certificate of insurance?: A certificate of insurance (COI) is a one-page document proving a business has active insurance. It summarizes the carrier, policy numbers, coverage types and limits, and effective dates (usually on an ACORD 25 form) and is issued to a client, landlord, or partner as proof of coverage. It isn't the policy itself and doesn't change the coverage the policy provides.
What is the purpose of a certificate of insurance?: Its purpose is to give a third party (a client, landlord, or general contractor) quick, shareable proof that a business holds the required coverage before work begins or a lease starts. It transfers financial risk to the contractor's insurer if their work causes injury or property damage, without exposing the full policy contract.
Where do I get a certificate of insurance?: Request a COI from your insurance agent, broker, or carrier. Many providers let you generate one from your online account, often free of charge. Tell them who the certificate holder is and any coverage or additional-insured requirements from the contract, so the certificate matches what the requesting party asked for.
What does "additional insured" mean on a COI?: Being named as additional insured means the certificate holder gets coverage under the policyholder's policy for claims arising from the insured's work. A client often requires this so they're protected if the contractor's work causes a loss. It's stronger protection than simply being listed as the certificate holder.
How long should I keep certificates of insurance?: Keep each COI at least as long as the contract or relationship it covers, plus the statute of limitations on related claims, commonly three to six years. If a vendor's work later causes a loss, the COI on file proves they were insured at the time, which is exactly when you'll need it.

Sources

This page is checked against primary and authoritative sources:

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