A certificate of insurance from a subcontractor proves that the subcontractor had coverage on the day the certificate was issued. It is not a contract, it does not modify the underlying policy, and it does not guarantee that the coverage will respond to your claim. The work of real subcontractor risk management is in the endorsements you require on the underlying policy, the verification you do before the subcontractor sets foot on your job, and the tracking you maintain across the life of the contract.
Most contractors and commercial buyers treat the COI as the deliverable. It is not. The COI is the evidence; the deliverable is the underlying insurance program—specifically, three endorsements that have to be present on the subcontractor’s general liability policy: additional insured status on your behalf, waiver of subrogation in your favor, and primary and non-contributory language. Without those three, the COI on file is paperwork, not protection. With them, the subcontractor’s policy actually responds when a claim names you alongside the sub.
- What does a certificate of insurance actually prove—and what does it not prove?
- What endorsements should a subcontractor’s policy carry before you let them on the job?
- How do you verify a certificate of insurance is real?
- What do you do when a subcontractor’s certificate is wrong or expires mid-job?
- How does Avanti Group review subcontractor COIs during a Diagnostic?
- Frequently Asked Questions
What does a certificate of insurance actually prove—and what does it not prove?
A certificate of insurance is a one-page summary issued by a subcontractor’s broker that lists the carrier, the policy numbers, the policy effective and expiration dates, and the limits in force. The standard ACORD 25 form is the document almost every commercial buyer in Iowa has seen.
A COI proves that the policies listed were in force on the date the certificate was issued. That’s the entire scope of what it proves. It does not amend, modify, extend, or alter the underlying policy. The fine print on the certificate itself says so, in language drafted by the insurance industry specifically to prevent buyers from treating the COI as a contract.
A COI does not prove that you are an additional insured. It can say “Additional Insured: [your company]” in the description box. That language by itself does not grant additional insured status; the endorsement on the underlying policy does. If the endorsement is missing from the policy, the COI is wrong—and a wrong COI does not create coverage that the policy did not include.
A COI does not prove that the coverage will be in force at the time of a claim. The subcontractor may let the policy lapse, the carrier may cancel for nonpayment, the policy may be amended mid-term, or a future renewal may drop the endorsements you required. The certificate is a snapshot on its issue date, and stale certificates expire.
A COI does not show sublimits, exclusions, or conditions. It shows the headline limits. As policy fine print walks through in detail, the actual coverage scope is decided by what is in (and not in) the policy form—not by the dec page numbers the COI repeats.
For a commercial buyer, the practical implication: the COI is the trigger to do the real work. It is not the work itself.
What endorsements should a subcontractor’s policy carry before you let them on the job?
Three endorsements on the general liability policy carry the real risk transfer. Every subcontractor agreement worth signing requires all three.
Additional insured status, ongoing AND completed operations. The standard ISO endorsements are CG 20 10 (ongoing operations) and CG 20 37 (products and completed operations). Together they extend the subcontractor’s CGL to cover you for liability arising out of the subcontractor’s work, both while the work is in progress and after it is complete. Most contracts that ask only for “additional insured” status end up with CG 20 10 only—which means once the project is done, the subcontractor’s policy stops protecting you for completed-operations exposure that may not surface for years. For a deeper read of what each endorsement actually grants, see the additional insured walkthrough.
Waiver of subrogation in your favor. Without it, the subcontractor’s carrier can step into the subcontractor’s shoes after paying a claim and recover against you—even when you were not at fault. The waiver of subrogation endorsement bars that recovery. It is critical for general contractors, property owners, and prime contractors who would otherwise be the target of a subrogation action by their own subcontractor’s insurer.
Primary and non-contributory language. Without it, when a claim names both you and the subcontractor, the carriers fight over which policy pays first. The fight delays defense, fragments coverage, and often forces your own policy to pay before the subcontractor’s. Primary and non-contributory language puts the subcontractor’s policy in line ahead of yours; your policy responds only after the subcontractor’s limits are exhausted.
Beyond those three, the underlying limits matter. A subcontractor whose CGL stops at $1 million per occurrence is materially under-coverage for projects where the contractual indemnification can reach $5 million or more. A commercial buyer with a $5 million commercial umbrella sitting on top of its own CGL is exposed if the subcontractor’s program does not carry a comparable limit ladder. The right COI request specifies a minimum limit—commonly $1 million per occurrence and $2 million aggregate on CGL, with a $1 million or $5 million umbrella stacked on top—and the verification step is to confirm both the underlying and excess policies are in force.
How do you verify a certificate of insurance is real?
A COI you accept without verification is paperwork the subcontractor’s broker emailed you. Verification turns it into evidence.
Step one: read what the COI actually says. The named insured at the top should match the legal entity the subcontractor agreement is signed with. The policy effective dates should span the entire work period (a COI that expires mid-project is a COI that does not cover the second half of the work). The certificate holder field should name your legal entity, not a generic d/b/a. The description box should list the specific endorsements—not just “additional insured” but the form numbers (CG 20 10 04 13, CG 20 37 04 13, the waiver of subrogation form, and the primary-and-non-contributory form).
Step two: call the broker, not the subcontractor. The phone number on the COI is the producer’s. Call and ask them to confirm that the endorsements listed are actually on the policy. A broker who cannot confirm without checking is a broker whose certificate you should not trust until they do check. A broker who can confirm should also send you the actual endorsement forms—not just the COI—as PDFs. The endorsements are the evidence; the COI is the index.
Step three: confirm cancellation notice. Standard COIs no longer guarantee cancellation notice will be sent to the certificate holder. If the underlying policy is cancelled mid-term, you may not learn about it until you ask. Some contracts require a written cancellation-notice endorsement that obligates the carrier (not the broker) to notify you. Confirm in writing that this is in place when the contract calls for it.
Step four: check the carrier. The COI lists the carrier names and AM Best ratings. A subcontractor insured by a non-admitted or low-rated carrier is a different risk than a subcontractor insured by a top-rated standard-market carrier. The carrier matters when the claim arrives.
Step five: log it. A pile of PDFs in an email inbox is not a tracking system. The COIs need to live in a contractor-management or COI-tracking platform (or at minimum, a structured folder with named files and expiration dates) so that expirations are flagged before they happen.
What do you do when a subcontractor’s certificate is wrong or expires mid-job?
The hard cases are not the missing COI. They are the wrong COI and the lapsed COI.
A wrong COI—one that names the wrong certificate holder, omits a required endorsement, or shows limits below contractual minimums—is a stop-work condition. The subcontractor should not be on the site until the COI is fixed. The agreement that governs the relationship should make that explicit: a sub whose insurance evidence does not match the contract requirements is a sub who is in breach, and the appropriate response is to pause work and demand corrected evidence (and the underlying endorsement PDFs) before resuming.
A lapsed COI mid-job is more common than most owners realize. Subcontractor policies renew on their own schedule, not on the project schedule. A policy that expires three months into a six-month build is a policy that needs a new COI issued at renewal. The tracking system should flag pending expirations 30 days out and demand the renewal evidence before the old policy lapses. If renewal evidence does not arrive on time, the contractual response is the same as for a wrong COI—pause work.
The most expensive subcontractor claims in Iowa commercial construction are the ones where the COI was on file when the work started and nobody re-verified at renewal. The endorsements that were present at binding were not present at the second renewal. The claim arrived two years later. The certificate that the general contractor had on file was a snapshot from a different policy year.
How does Avanti Group review subcontractor COIs during a Diagnostic?
Avanti Group does not start a general liability insurance review with a market shop. Before any quote, the team runs a Business Risk Diagnostic™—a structured walk through the operation, the contracts the business has signed with its customers and the contracts it has signed with its subcontractors and vendors, the COIs currently on file from those subs and vendors, and three-to-five years of loss runs to see whether the contract-driven risk transfer has actually held up at claim time.
For commercial buyers who use subcontractors—general contractors, property managers, manufacturers with outside service providers, hospitality operators who hire vendors on-site—the Diagnostic flags the COIs that are missing endorsements, the contracts that require endorsements the COIs do not match, and the gaps where the buyer is carrying risk it thought a subcontractor’s policy was covering. The output is a written list of corrections to demand from each subcontractor’s broker, ordered by exposure. For a business that has signed dozens of subcontractor agreements, that document is the only practical way to surface the gaps before the next claim does.
The principle: contract risk transfer fails one of two ways—either the contract does not actually transfer the risk it appears to transfer, or the insurance evidence does not match the contract. Both failures are quiet until a claim arrives. Both are fixable before the claim arrives. Both are exactly what a Business Risk Diagnostic™ is designed to surface.
Frequently Asked Questions
What is the difference between a certificate of insurance and an endorsement?
A certificate of insurance is a one-page summary issued by a broker that lists what coverage is in force on the date of issuance. It is not part of the policy and does not modify the policy. An endorsement is an addition or change to the actual policy form, written by the carrier, that grants, restricts, or modifies coverage. Additional insured status, waiver of subrogation, and primary and non-contributory language all live on endorsements—not on the certificate. The certificate is the index; the endorsements are the evidence. When a contract requires those provisions, the right verification step is to obtain the actual endorsement PDFs from the subcontractor’s broker, not just the COI.
What is the difference between CG 20 10 and CG 20 37 on a subcontractor’s policy?
CG 20 10 grants additional insured status for ongoing operations—coverage while the subcontractor’s work is in progress. CG 20 37 grants additional insured status for products and completed operations—coverage after the work is finished. Construction-related claims often surface years after completion, and a CG 20 10 alone does not cover them. The contract should require both endorsements for any subcontractor whose work creates completed-operations exposure (general construction, mechanical, electrical, roofing, finish trades, and most service work performed on the customer’s property).
What minimum insurance limits should a contract require from a subcontractor?
The standard floor in most commercial subcontractor agreements is $1 million per occurrence and $2 million general aggregate on commercial general liability, with a separate $2 million products and completed operations aggregate; $1 million combined single limit on commercial auto; statutory workers’ compensation; $1 million employers’ liability; and a commercial umbrella of $1 million to $5 million stacked on top. Higher-risk trades (heavy construction, demolition, roofing, mechanical) often require $5 million or higher towers. The right minimum is the higher of contractual requirement (from your own customer contract or lease), underwriter recommendation for the work scope, and the limit the subcontractor’s exposure profile actually justifies.
How often should a commercial buyer verify a subcontractor’s certificate of insurance?
At least at every policy renewal listed on the COI, and ideally any time the subcontractor’s policy is amended mid-term. Many subcontractor policies renew annually but project schedules run longer than that, so a COI on file at project start is often stale by month twelve. A tracking system should flag the renewal date 30 days out and demand fresh evidence (and updated endorsement PDFs) before the old policy expires. For high-value or multi-year projects, mid-term spot checks make sense as well.
What happens if a subcontractor’s policy is cancelled mid-project?
Coverage stops on the cancellation date. The COI that was on file becomes evidence of past coverage, not current coverage. Standard ACORD certificates do not commit the carrier to notify the certificate holder of cancellation; that obligation has to be added by endorsement and confirmed contractually. If a cancellation occurs and the subcontractor remains on site without replacement coverage, the contractual response is to suspend work, demand evidence of replacement coverage with the same endorsements, and document the gap in writing. A claim that arises during an uninsured gap is a claim the subcontractor (and potentially the buyer) absorbs out of pocket.