Primary and Noncontributory vs Waiver of Subrogation

Last updated August 2026.

No, they are not the same thing. Primary and noncontributory decides which insurer pays first and stops one insurer billing another for a share of the loss. A waiver of subrogation stops the vendor's insurer coming after you personally to recover what it already paid. One governs how two insurance companies split a bill. The other governs whether you get sued after the bill is settled.

They end up in the same sentence of the same contract so often that people treat them as a single requirement. Then a claim happens, one of the two turns out to be missing, and the difference becomes expensive. Here is what each one actually does.

Is primary and noncontributory the same as a waiver of subrogation?

No. They protect you at different moments in the life of a claim. Primary and noncontributory operates while the claim is being paid: it keeps your own insurer out of the settlement. A waiver of subrogation operates after the claim is paid: it stops the vendor's insurer turning around and suing you to get its money back. You can have either one without the other, and plenty of vendors do.

What primary and noncontributory actually does

Every liability policy contains an Other Insurance condition explaining what happens when two policies could pay the same claim. Left alone, that condition lets insurers share the loss between them. If you are an additional insured on your vendor's policy and you also carry your own general liability cover, both insurers can be at the table, and yours can end up contributing to a loss your vendor caused.

The ISO endorsement CG 20 01, Primary And Noncontributory, Other Insurance Condition, rewrites that. It states the insurance is primary to and will not seek contribution from any other insurance available to an additional insured under the policy. The vendor's carrier pays the whole loss up to its limits and does not ask yours for anything.

There is a catch worth knowing before you rely on it. The wording only engages if two conditions are both true: the additional insured has to be a Named Insured under the other insurance, and the vendor has to have agreed in writing that its insurance would be primary and noncontributory. If your insurance requirements clause never says those words, the endorsement can sit on the policy doing nothing at all.

What a waiver of subrogation actually does

Subrogation is the right an insurer inherits after paying a claim: it steps into its insured's shoes and pursues whoever caused the loss. A vendor's carrier pays its own insured for a fire, decides your maintenance contractor caused it, and sues you. The claim was settled months ago and you are still a defendant.

A waiver of subrogation endorsement is the insurer agreeing in advance not to do that to a named party. On general liability that is CG 24 04. On workers compensation it is the waiver of our right to recover endorsement, and it is the one that most often goes missing, partly because comp waivers carry a real additional premium while liability waivers usually do not.

The December 2019 edition of CG 24 04 added a condition that catches people out: the waiver applies only to the extent the insured waived its own right of recovery before the loss. A mutual waiver of claims in your contract, signed before work started, is what makes that condition true. Signed afterwards, the endorsement is on the policy and the protection is not.

Where additional insured status fits

Contracts almost always name a third requirement alongside these two, and it is the foundation both of them sit on. Additional insured status, granted by a CG 20 series endorsement, is what makes you an insured under the vendor's policy in the first place. Without it there is no coverage to be primary and nothing for the other two requirements to modify.

The three do genuinely different jobs. Additional insured status gets you a defense and coverage under someone else's policy. Primary and noncontributory keeps your own insurer out of paying for it. A waiver of subrogation stops that same insurer recovering from you afterwards. A contract that requires only the first has left two of the three doors open, which is the most common drafting gap we see in real subcontracts and leases. If you are working through a stack of leases to find out what each one actually demands, pulling the insurance clause out of every document is a job worth abstracting systematically rather than reading lease by lease.

A worked example

A tenant improvement contractor drops a tool through a sprinkler head. The building floods. Damage runs to $400,000, and the property manager and the building owner are both named additional insureds on the contractor's general liability policy.

With additional insured status alone: the contractor's insurer covers the claim, but its Other Insurance condition lets it approach the property manager's own liability carrier for a contribution. Say it recovers $150,000. The property manager now has a paid claim on its loss history and a renewal conversation it did not earn.

Add CG 20 01 and the vendor's insurer pays the full $400,000 and asks for nothing. Add the waiver of subrogation and, if the insurer later decides the property manager's own maintenance staff contributed to the loss, it cannot sue to get its money back. Three requirements, three separate failure points, and the certificate on file evidences exactly one and a half of them.

Why the certificate can prove one and not the other

This is the part that surprises people reviewing certificates for the first time. The ACORD 25 grid carries two endorsement columns: ADDL INSR and SUBR WVD. So a waiver of subrogation at least has a checkbox, weak evidence though a checkbox is, since somebody at the agency typed it.

Primary and noncontributory has no column at all. There is nowhere on the form to record it. The only place it can appear is as free text in the Description of Operations box, and only if whoever prepared the certificate thought to type it. A reviewer working through certificates by scanning the checkbox columns will approve vendor after vendor who never bought CG 20 01, and nothing on the document will look wrong.

The fix is the same for all three requirements: read the endorsement pages, not the certificate face. Ask for CG 20 01 and CG 24 04 by form number, check the edition dates in the corner of each page, and confirm the coverage line matches. A vendor who sends only a certificate has sent you a summary of a document set rather than the document set. Once the volume passes a few dozen vendors, reading endorsements at that level of detail stops being something a person can keep up with by hand.

Do I need both primary and noncontributory and a waiver of subrogation?

If your contract transfers real risk to vendors, yes. They close different gaps and neither implies the other. The standard construction and property management requirement is all three together: additional insured status on a CG 20 series form, primary and noncontributory on CG 20 01, and a waiver of subrogation on CG 24 04, extended to the auto and workers compensation lines where the vendor's work touches them.

Which comes first if a vendor can only get one?

Take the waiver of subrogation. A missing primary and noncontributory endorsement costs you a shared loss and a mark on your loss history. A missing waiver leaves you exposed to a recovery action for the full amount, years after the work, with your own defense costs on top. The downside is larger and it arrives when the file is long closed.

Can primary and noncontributory be added after a contract is signed?

The endorsement can be added to the policy at any time by the vendor's carrier, and it will apply to losses from its effective date forward. What cannot be fixed retroactively is a loss that already happened. Both requirements are worth confirming before work starts rather than at the point somebody needs them, because that is the one moment neither can be arranged.

For the full set of forms behind each requirement, with the policy wording quoted from issued endorsements, see the certificate of insurance endorsements reference and the additional insured endorsement forms page.