Primary and Noncontributory: What It Means on a Sub's COI and Why You Must Require It
Primary and noncontributory means a sub's insurance pays first for a claim against you, and their insurer can't make your insurer share the bill. Without it, a loss your sub caused can land on your own policy and your own loss history. This guide covers what each half means, how it plays out in a claim, where it shows up on the certificate and the policy, and how to require and check it.
Primary and noncontributory is a provision that makes a subcontractor's or vendor's liability policy pay first for a covered claim against you as an additional insured (primary), without seeking a share from your own policy (noncontributory). It only works alongside additional insured status. The ACORD 25 has no checkbox for it, so the proof is the endorsement on the policy — usually ISO form CG 20 01, or wording inside the carrier's blanket additional insured form.
In this guide
What primary and noncontributory means
When you are named as an additional insured on a sub's general liability policy, two policies can now respond to the same claim against you: theirs, and your own. Every liability policy has an "Other Insurance" condition that decides what happens then. Primary and noncontributory rewrites that condition in your favor. It has two halves, and they do different jobs:
Primary
The sub's policy responds first, before your own, for a covered claim against you. Your policy sits behind it as excess.
Noncontributory
The sub's insurer won't seek contribution from your insurer — no pro-rata split, no share of the defense costs — while its own limits last.
The two are usually written together, but they aren't the same promise. A policy can be primary and still contributory, paying first but then asking your insurer for its share. You want both. And neither means anything on its own: primary and noncontributory decides the order in which policies pay you, so it only exists on top of additional insured status. If certificate holder vs. additional insured is still a blur, start there.
How it plays out in a claim
A drywall sub's crew leaves a cart on a stair landing. A visitor trips, and sues both the sub and you as the GC. You are an additional insured on the sub's policy. What happens next depends on whether that coverage is primary and noncontributory:
| Without it | With primary and noncontributory | |
|---|---|---|
| Who defends you | Both insurers may argue over who goes first, and your own carrier is pulled in | The sub's insurer, from the start |
| Who pays | The loss can be split between the two policies, by equal shares or by limits | The sub's policy, up to its limits; yours only above them |
| Your loss history | A claim paid partly by your carrier, on your record at renewal | Your policy untouched unless the sub's limits run out |
| Your deductible | May apply to your share | Not triggered |
That is the whole point of requiring it: the sub's insurance, which you required precisely so the sub's losses stay theirs, actually keeps them theirs. Owners and property managers want the same thing from their contractors and vendors, which is why prime contracts and management agreements so often require it and expect you to flow it down to every sub. For the full set of coverages to require, see general contractor insurance requirements.
Where it appears: the certificate and the endorsement
The ACORD 25 has checkboxes for additional insured (ADDL INSD) and waiver of subrogation (SUBR WVD). It has no box for primary and noncontributory. Agents usually type it into Description of Operations — "Certificate holder is additional insured on a primary and noncontributory basis where required by written contract." That sentence tells you what the agent believes the policy says. It does not change the policy; the certificate states that it confers no rights.
The coverage itself lives in an endorsement on the policy, in one of two forms:
- ISO CG 20 01, Primary and Noncontributory — Other Insurance Condition. It makes coverage for an additional insured primary and noncontributory when a written contract requires it. Easy to misread: every other CG 20 form is an additional insured endorsement, and this one isn't.
- A carrier's own form — many insurers write primary and noncontributory wording directly into their blanket additional insured endorsement, so there is no separate CG 20 01 to find. Read the additional insured form for the words.
Either way, the condition is usually "where required by written contract". If your subcontract doesn't require it, the endorsement may not give it to you. The additional insured form it rides on matters too — see CG 20 10 vs CG 20 37 for ongoing versus completed operations.
How to require it and check it
Put it in the subcontract
The insurance exhibit should require the sub's general liability — and umbrella or excess — to be primary and noncontributory with respect to any insurance carried by you and the owner, with both named as additional insureds. Have your attorney set the wording once.
Ask for the endorsement, not just the certificate
Request the CG 20 01, or the additional insured form that contains the primary and noncontributory wording, with every new certificate. A note in Description of Operations is a starting point, not proof.
Check the umbrella too
If the claim exceeds the sub's general liability limits, their umbrella should respond before your policy does. Ask that it follow form and be primary and noncontributory over your coverage.
Check it again at renewal
Endorsements can change when a policy renews or moves to a new carrier. A sub who had it last year may not have it on this year's policy.
Reading endorsement pages by hand for every sub at every renewal is the step that slips first. Insurance endorsement verification reads the forms themselves, and COI tracking software keeps each policy on its own dates so the renewal check happens. For the other things to confirm on a certificate, use the COI audit checklist.
How TrackMyVendor automates this
- Endorsement forms are read, and a CG 20 01 is recognised as primary and noncontributory by its form number, even when it arrives titled as something else. Pro
- Make the primary and noncontributory endorsement a required document, and a sub whose policy doesn't show one is flagged until it arrives. Pro
- Every coverage row on the certificate is read by AI — carrier, policy number, dates and limits — and each policy is tracked on its own expiration.
We read the endorsement forms you're sent; we don't read the subcontract or confirm the "where required by written contract" condition is met. That stays with you and your attorney.
See how endorsement verification worksCertificates and endorsements, collected together
Subs and vendors upload the certificate and the endorsement pages through one link — no account, no portal. Every policy is read and tracked on its own dates. Your first 25 contractors are free.