How to Read a Certificate of Insurance (COI): A General Contractor's Guide

TL;DR: A Certificate of Insurance (ACORD 25) is a one-page snapshot of a subcontractor's coverage issued by their broker; it does not grant coverage and is invalid the day it expires. Verify the insured's exact legal name, GL/Auto/Umbrella limits, additional-insured endorsement form numbers (CG 20 10, CG 20 37), and effective dates before letting the sub on site.

Every general contractor has lived this moment: a subcontractor finally sends their Certificate of Insurance, you open the PDF, and you're looking at a dense, tiny, one-page form with eight different boxes, twenty acronyms, and a signature at the bottom. Is this the right coverage? Is the GC named correctly? Is there a problem you're about to miss?

This guide walks you through exactly how to read a COI, section by section, so you can verify subcontractor coverage in under 60 seconds and flag the things that actually matter.

What Is a Certificate of Insurance?

A Certificate of Insurance (COI) is a one-page document issued by an insurance agent or broker that summarizes the coverage a policyholder carries. It does not grant coverage, amend a policy, or bind the insurer to anything. It's a snapshot, a promise from the agent that on the day the certificate was issued, these policies existed with these limits and these terms.

For general contractors, a COI is how you verify that each subcontractor has the insurance you require before they step onto your jobsite. For owners and upstream GCs, it's how they verify you carry the insurance you said you would.

The ACORD 25 Form: The Industry Standard

The vast majority of COIs you'll receive are issued on a form called ACORD 25, the "Certificate of Liability Insurance." The ACORD Corporation is an industry-standards body, and the ACORD 25 is the universal template used by essentially every US insurance agency. When you see the ACORD logo in the top-left corner, you know what you're looking at.

The form has seven main sections. Here's what each one contains and what to check.

Section 1: Producer

Top-left box. This is the insurance agency or broker who issued the certificate. You'll see:

• Agency name
• Address
• Contact person
• Phone, fax, email

What to check: The contact info is real. If a COI comes from "John's Insurance" with no phone number, that's a red flag. Legitimate certificates come from named agents at named agencies. If you have any concerns, call the producer directly and ask them to confirm the COI was issued from their office for this project.

Section 2: Insured

Top-right box. This is the subcontractor, the company the policy actually covers. You'll see:

• Legal business name
• Mailing address

What to check: The insured name matches exactly the company name on the sub's contract and W-9. This sounds obvious but trips up GCs constantly. "ABC Contracting LLC" and "ABC Contracting, Inc." are different legal entities. If the COI is in the wrong entity's name, coverage may not apply.

Section 3: Insurers Affording Coverage

A small table listing the insurance companies providing coverage, usually labeled A, B, C, D, E. Each letter maps to a row in the coverage table below. Each entry shows the carrier name and the NAIC number (a five-digit identifier for US insurers).

What to check: All carriers are A- or better rated by AM Best. You can look up any carrier by NAIC number on ambest.com. Carriers with financial strength ratings below B+ are a concern because they may not be able to pay a claim if one occurs.

Section 4: Coverages (The Big One)

This is the main table in the middle of the form and the most important part of the certificate. Each row represents a different type of insurance policy. For a standard subcontractor, you'll usually see four:

Commercial General Liability (CGL)

The most important line. Covers bodily injury and property damage the sub might cause on your jobsite. Check:

• Each Occurrence: Typically $1,000,000 minimum. This is the most the policy will pay for a single incident.
• General Aggregate: Typically $2,000,000 minimum. The total the policy will pay across all claims in a year.
• Products-Completed Operations Aggregate: Also typically $2,000,000. This matters for anything built or installed because it covers the sub's work after the job is done.
• Per Project Aggregate: Look for a checkbox or notation that aggregate limits apply per project rather than across the whole policy year. Without this, one big claim elsewhere can eat the sub's entire aggregate and leave your project uncovered.
• Occurrence vs Claims-Made: Look for a checkbox. "Occurrence" is standard for construction and what you want. "Claims-Made" policies only cover claims reported while the policy is active, which is problematic for construction work that might generate claims years later.

Automobile Liability

Covers vehicles the sub owns, hires, or uses for work. Check:

• Combined Single Limit (CSL): Typically $1,000,000 minimum.
• Any Auto / Owned / Hired / Non-Owned: Look at which boxes are checked. "Any Auto" is the broadest; "Hired and Non-Owned" is the narrowest and may not be enough if the sub owns work trucks.

Umbrella / Excess Liability

Provides coverage above the underlying GL and Auto limits. Not always required but common on larger projects. Check the limit and whether it's listed as "Umbrella" (broader, fills gaps) or "Excess" (only follows underlying form).

Workers' Compensation and Employers Liability

Covers the sub's employees if they're injured on the job. Check:

• Statutory / Per Statute: The WC line should show "statutory" limits, meaning coverage as required by state law.
• Employers Liability Limits: Usually $1,000,000 / $1,000,000 / $1,000,000 (per accident, disease-policy limit, disease-each employee).
• Is there a Workers' Comp line at all? If the sub is a sole proprietor with no employees, they may be exempt, but you should get a Workers' Comp Exemption Certificate instead. Never accept "we don't have WC" as a sufficient answer.

Policy Dates

Every row has an Effective Date and an Expiration Date. Check:

• The effective date is before or equal to the project start date (no retroactive gaps).
• The expiration date is after the project completion date.
• If the project will extend past expiration, make a note to request a renewal certificate 30 days before expiration.

Section 5: Description of Operations, Locations, Vehicles

The free-text box in the lower third of the form. This is where critical endorsement language lives, and it's where most GCs miss things. Look for:

• "[Your GC name] is named as Additional Insured": this is the endorsement that makes you a protected party under the sub's GL policy. If it's missing, your contract language is meaningless.
• "Primary and Non-Contributory": language confirming the sub's policy pays first before yours. Without this, your insurance may be forced to contribute to a claim even though the sub caused it.
• "Waiver of Subrogation": the sub's insurer waives their right to sue you after paying a claim their insured caused.
• The project name, number, or address: shows this specific certificate was issued for this specific job. Generic "blanket" language is acceptable if the underlying endorsement is blanket, but project-specific is cleaner.

This is the section that matters most for your protection as a GC. If any of the above language is missing, the coverage you think you have may not actually exist. Send the COI back to the producer and ask for a revised certificate with the missing endorsements.

Section 6: Certificate Holder

Lower-left box. This is you, the party the certificate was issued to. Check:

• Your company name is correct and spelled right
• Your address is correct
• Any project name or number is listed

A sub sometimes sends the same COI to multiple GCs by changing only the certificate holder box. That's fine, but verify the holder name actually matches you.

Section 7: Cancellation

Lower-right box. Standard ACORD 25 language says the insurer will try to mail notice of cancellation but is under no obligation to do so. This wording changed around 2010 and no longer provides meaningful protection. Don't rely on it to warn you of a lapse.

This is why automated expiration tracking matters more than ever. Since you can't count on the insurer to notify you when coverage cancels, you need a system that watches expiration dates and alerts you before the sub's coverage lapses.

Red Flags: What to Reject

Send any of these back to the producer for correction before you let the sub on site:

1. The insured name doesn't match the sub's legal business name
2. The policy effective date is after your project start date (retroactive gap)
3. The limits are below your contract requirements
4. No Additional Insured language in Description of Operations
5. No Primary and Non-Contributory language
6. No Waiver of Subrogation (if your contract requires it)
7. Workers' Comp line is blank and no exemption certificate was provided
8. A carrier with a below-B+ AM Best rating
9. "Claims-Made" general liability (should be "Occurrence")
10. The certificate is more than 30 days old (request a fresh one)

How to Automate COI Review

Reading every COI manually works when you have five subs. With fifty subs on three projects, it breaks down. You forget to check things, certificates expire without anyone noticing, and endorsement gaps slip through.

PaperBoss is COI tracking software built specifically for GCs managing subcontractor compliance. It collects certificates via secure upload link (no account needed for subs), captures effective and expiration dates automatically, gives you an Additional Insured checklist on every certificate, and sends expiration alerts at 90, 60, and 30 days so you're never surprised by a lapse.

If you're ready to stop reading COIs one at a time, start a 14-day free trial, no credit card required.

Frequently Asked Questions

Is a COI legally binding?

No. A COI is an informational document. It does not grant coverage or amend the underlying policy. The only binding documents are the policy itself and any endorsements attached to it. A COI is evidence of what exists, not proof that it will be there when you need it.

How long is a Certificate of Insurance valid?

A COI itself doesn't have a validity period. What matters are the effective and expiration dates of the underlying policies. Most construction policies are annual, so a COI is usually "valid" for up to a year, after which you should request a renewal certificate.

What happens if a subcontractor's insurance expires mid-project?

If an incident occurs while coverage is lapsed, the sub's insurer will deny the claim. Liability can then transfer back to you, the GC. This is the #1 reason GCs need continuous expiration tracking, not just point-in-time verification at project kickoff.

Who is responsible for providing a COI?

The subcontractor provides it, typically via their insurance agent or broker. You, the GC, set the requirements in your subcontractor agreement and enforce them by withholding work authorization until a compliant COI is on file.

Can a subcontractor use the same COI for multiple GCs?

Only if each GC is named as a certificate holder and as an additional insured on the sub's policy. Otherwise, each GC needs their own certificate issued by the producer.

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This article is for educational purposes and doesn't constitute legal or insurance advice. Always consult with a licensed insurance broker for specific coverage questions.