Subcontractor Insurance Requirements: The GC’s COI Guide (2026)

The audit bill nobody warns you about

Most general contractors treat subcontractor certificates as paperwork: collect a PDF, drop it in a folder, move on. Then the annual premium audit arrives, and the contractor who skipped a certificate gets a bill for thousands of dollars they never budgeted for. This is the single most expensive mistake in subcontractor insurance, and almost no one is warned about it.

Here is the mechanic. When your general liability and workers’ compensation policies are audited, the auditor looks at everyone you paid to do work. For any subcontractor who cannot show they carried their own coverage, that sub’s cost is treated as your exposure. On a workers’ comp audit, the auditor may treat what you paid an uninsured sub as your own payroll and charge you premium for it, even for legitimate 1099 subcontractors. Travelers states it plainly: without a valid certificate of workers’ compensation insurance, the carrier may charge a premium for work performed by a subcontractor.

That is why subcontractor compliance is not administrative busywork. It is direct protection of your own premium, on top of protecting you from inheriting a sub’s liability claim. The rest of this guide is what to require, in what form, and how to verify it so the paper actually holds up.

What to require from every subcontractor

Before a subcontractor sets foot on your job, require these five things in writing. Put them in the subcontract, not just the purchase order, so the requirement survives a dispute.

Two of these are widely misunderstood, and they are exactly where compliance breaks down: the difference between being a certificate holder and an additional insured, and the fact that additional insured status takes two separate endorsements, not one. We cover both next. For a ready-to-use system to collect and track all five items, see our subcontractor insurance compliance page.

The number one mistake: certificate holder is not additional insured

When a subcontractor lists you on their ACORD 25, you usually appear in the certificate holder box in the bottom left. Many contractors see their name there and assume they are covered under the sub’s policy. They are not.

The certificate itself says so. The ACORD 25 states that it is issued as a matter of information only and confers no rights upon the certificate holder, and that it does not amend, extend, or alter the coverage the policies provide. Being a certificate holder means one thing: you received a copy of the certificate. That is all.

Coverage is extended to you only when you are named an additional insured by endorsement on the sub’s policy. An additional insured can access the sub’s policy directly and tender a defense to the sub’s insurer. The certificate should then show the additional insured status, but the status comes from the endorsement, not from a line typed on the certificate. If the certificate claims additional insured status but no endorsement backs it, you have paper without protection. Read more on the additional insured endorsement and how it differs from a certificate.

The two additional insured endorsements you actually need

Here is the detail that trips up even experienced contractors: additional insured status for construction work takes two separate ISO endorsements, and requiring only one leaves a hole that opens after the job is done.

The trap is that CG 20 10 alone does not respond to completed-operations claims. A roof leak, a wiring fault, or a foundation crack blamed on a sub often shows up months or years after the sub demobilized, which is squarely a completed-operations claim. If you only required the ongoing-operations form, the sub’s insurer can decline to defend you on that later claim. Require both CG 20 10 and CG 20 37 from every sub whose work you could be blamed for after completion. Our guide to additional insured, primary and noncontributory, and waiver of subrogation breaks down the endorsement wording GCs ask for.

Waiver of subrogation from your subs

Subrogation is the right of an insurer, after it pays a claim, to step into the shoes of its policyholder and recover the money from whoever it thinks was at fault. Without a waiver, a subcontractor’s insurer can pay a claim and then come after your company to get its money back, which defeats the point of requiring the sub to carry coverage in the first place.

A waiver of subrogation in your favor blocks that recovery. Like additional insured status, it has to be added by endorsement to the sub’s policy and backed by the contract language; a note on the certificate is not enough. Require the waiver on both the sub’s general liability and, where your contract calls for it, their workers’ compensation.

The ACORD 25 certificate, and the 2025 edition change

The certificate a sub gives you is almost always an ACORD 25, Certificate of Liability Insurance, the standard industry form for evidencing general liability and related coverages. In December 2025, ACORD issued a new edition, ACORD 25 (2025/12), its first revision since the 2016/03 edition. If you are reviewing certificates in 2026, expect to see the newer edition arriving alongside the old one during the transition.

Whatever the edition, the certificate’s core limitation is unchanged: it is a snapshot of coverage on the day it was issued, and it confers no rights by itself. It can be accurate the day you receive it and meaningless a month later if the sub’s policy was cancelled. That is why collecting one certificate at the start of a project is not compliance; the coverage has to be in force for the whole time the sub is exposing you to risk. If you need to issue a certificate to your own GC quickly, see how to get a same-day certificate of insurance.

How to actually verify a subcontractor’s COI

Collecting a certificate is not the same as verifying it. A quick review catches the mistakes that get certificates rejected in vendor portals and leave you exposed at audit. Check each of these:

• Your company is named correctly as certificate holder, and as additional insured if the contract requires it (with the endorsement to back it)
• The limits meet your contract, usually $1M per occurrence and $2M aggregate for general liability
• The policy dates cover the full period the sub will be on your job, not just the start date
• Additional insured is by endorsement, ideally with the CG 20 10 and CG 20 37 form numbers shown or the endorsements attached
• Workers’ compensation is present (or a valid exemption), so the sub’s payroll does not land on your audit
• A waiver of subrogation appears where your contract requires it
• The certificate is current, and you have a process to collect a renewal certificate when the policy renews mid-project

Build this into a repeatable system rather than a one-time check. Our subcontractor insurance compliance page walks through a simple step-by-step workflow you can copy, and our premium audit page covers what to have ready before the auditor arrives.

Why a subcontractor’s certificate gets rejected

If you pass a sub’s certificate up to your own general contractor or a project’s vendor portal, it can bounce back for reasons that have nothing to do with whether the sub is actually insured. These are the rejections we see most, and each is avoidable with a two-minute review before you submit:

• Certificate holder name does not match the contract exactly, down to the entity type (LLC vs Inc.) and spelling
• Additional insured is typed on the certificate but no endorsement is attached, so the portal cannot confirm the coverage is real
• Only the ongoing-operations endorsement is present when the contract also requires completed operations
• Limits are below the contract minimum, or a required umbrella or excess layer is missing
• The description of operations box is blank when the contract requires specific wording for the additional insured or waiver
• The policy dates have lapsed or expire before the project ends
• Primary and noncontributory wording is required by the contract but not shown or endorsed

Most of these are wording and documentation issues, not coverage gaps, which is exactly why they are frustrating: the sub has the insurance, but the paper does not prove it in the form the contract demands. When you are the one who needs a clean certificate issued fast for your own bid, a broker who handles the endorsements and certificate together saves the back-and-forth. That is what we do; request a quote or request a certificate and send the exact contract wording up front.

Key takeaways

• A certificate holder has no coverage; only an additional insured by endorsement does.
• Construction additional insured status takes two endorsements: CG 20 10 (ongoing) and CG 20 37 (completed operations). Require both.
• Add a waiver of subrogation so the sub’s insurer cannot recover from you after paying.
• No valid certificate on file at your premium audit means the sub’s payments can be charged as your own payroll or exposure, raising your premium.
• Verify limits, dates, endorsements, and workers’ comp on every certificate, and collect renewals mid-project.

Frequently asked questions

Sources

• IRMI — Additional Insured Status and Waivers of Subrogation
• IRMI — ISO Additional Insured Endorsements (construction)
• Travelers — General Liability Premium Audit
• ACORD — Forms (ACORD 25 Certificate of Liability Insurance)