Primary and noncontributory is a coverage status in which the named insured's policy pays a covered loss first and does not ask the additional insured's own insurance to contribute. Contracts pair it with additional insured requirements so the downstream party's policy absorbs the loss alone, leaving the upstream party's limits and loss history untouched.
You will see the phrase in the insurance requirements section of nearly every construction subcontract and commercial lease, and you will field certificate requests demanding it in writing.
Primary and Noncontributory
An other insurance arrangement in which the named insured's policy applies as primary and the insurer agrees not to seek contribution from other insurance available to an additional insured on the same basis.
How does the CG 20 01 endorsement work?
Without modification, the Other Insurance condition in CG 00 01 decides how overlapping policies share a loss, contributing by equal shares if the other policy permits it and otherwise pro rata by limits. An additional insured facing a claim would rather not share at all.
The CG 20 01 endorsement, Primary And Noncontributory Other Insurance Condition, edition 12 19, amends that condition so the named insured's policy is primary to the additional insured's own coverage and will not seek contribution from it. Two conditions gate the change: the person or organization must actually be an additional insured under the policy, and a written contract must require the coverage to apply on that basis.
IRMI's definition captures the second half of the phrase: noncontributory insurance will not seek contribution from other policies that apply to the loss on the same basis.
What does CG 20 01 not do?
It grants no additional insured status. This is the error that generates E&O files. CG 20 01 only rewires the Other Insurance condition, so an upstream party named nowhere else on the policy gets nothing from it. Status must come from an additional insured endorsement such as CG 20 10 for ongoing operations or CG 20 37 for completed operations, with CG 20 01 layered on top.
Check the contract wording against the forms before you issue the certificate, because sophisticated certificate reviewers reject COIs that recite primary and noncontributory without listing an endorsement number that actually delivers it. Remember too that the endorsement addresses sharing, not breadth: the additional insured still gets only the coverage the AI endorsement grants, capped by the named insured's limits and eroded aggregate.
Frequently asked questions
Does primary and noncontributory make someone an additional insured?
No. CG 20 01 only modifies the Other Insurance condition. Additional insured status must be granted separately, by an endorsement like CG 20 10 or CG 20 37 or by a blanket provision. The two requirements travel together in contracts but are met by different forms.
Is a certificate showing primary and noncontributory enough?
No. A certificate of insurance confers no coverage by itself. The wording must appear in the policy through CG 20 01 or equivalent language, and careful reviewers ask for the endorsement copy, not just the checked box on the ACORD form.
What happens without primary and noncontributory wording?
The Other Insurance conditions of both policies control. The additional insured's own insurer may be required to contribute by equal shares or pro rata, which puts a claim on the additional insured's loss runs, exactly what the contract meant to prevent.
Does CG 20 01 apply without a written contract?
No. The endorsement applies only when a written contract or agreement requires the insurance to be primary and not seek contribution. An oral agreement or a handshake requirement leaves the standard sharing provisions in place.
This definition is for educational purposes. Your policy's specific terms, conditions, and endorsements control. Talk to a licensed broker about your actual exposures.