Contracts say “primary and noncontributory” because a liability policy’s “other insurance” condition decides which insurer pays first and whether it can ask another insurer to share. Naming the customer as an additional insured generally makes your policy primary for that claim, but if the customer’s policy is also primary, the two share the loss unless yours says it won’t seek contribution. ISO endorsement CG 20 01 adds that sentence to the Other Insurance condition, on two conditions: the customer is a named insured on its own policy, and you agreed to primary and noncontributory in writing. Wording on a certificate doesn’t do it. The endorsement has to be on the policy, next to the additional insured endorsements the same contract asks for.
What the contract is asking for
Two public-agency contracts show the wording. The New York State Office of General Services bid attachment says all liability policies “shall be primary and non-contributory to other insurance available to” the agency, and any insurance the agency carries “shall be excess of and shall not contribute with” yours. Oregon DOT’s subcontractor exhibit says it in one line: coverage “shall be primary and noncontributory with any other insurance and self-insurance.”
The two words do two separate jobs. Primary means your policy pays before the other party’s policy or self-insurance. Noncontributory means your insurer won’t turn around and ask that other policy to split the bill, even if it also claims to be primary.
How “other insurance” clauses decide who pays
A liability policy’s “other insurance” condition says what happens when more than one policy covers the same loss. In the ISO general liability form, primary is the default; the policy is excess only in situations the condition lists. One is a loss where the named insured has been added to someone else’s policy as an additional insured by endorsement. So when your policy names the general contractor as an additional insured, the contractor’s own policy drops to excess by its own wording, and yours sits primary.
That handles “primary.” The catch is “noncontributory.” If two policies both end up primary, the condition tells them to share: equal shares when every policy allows it, otherwise in proportion to limits. Without noncontributory wording, both insurers share defense costs and damages. Self-insurance is different: the Florida court opinion IRMI quotes held that it is not “other collectible insurance,” and agencies that self-insure write the requirement to keep their retention out of the claim until your limits are used up.
The endorsement: ISO CG 20 01
The ISO endorsement for this is CG 20 01 04 13, “Primary and Noncontributory – Other Insurance Condition.” It is one page, attaches to the Commercial General Liability Coverage Part and the Products/Completed Operations Liability Coverage Part, adds a paragraph to the Other Insurance condition and “supersedes any provision to the contrary.” That paragraph makes the insurance primary to, and bars it from seeking contribution from, any other insurance available to an additional insured, on two conditions:
- The additional insured is a Named Insured on that other policy. It runs against the contractor’s own policy, not one where the contractor is just another additional insured.
- You agreed to it in writing. It applies only where “you have agreed in writing in a contract or agreement” that your insurance would be primary and noncontributory. A contract that only says “additional insured” doesn’t trigger it.
Neither agency contract above names CG 20 01. Both state the requirement in their own words and list the additional insured forms “or equivalent”; New York OGS also takes a blanket endorsement. “Equivalent” is the word to check: the wording has to do both jobs.
Why additional insured status alone isn’t enough
Additional insured and primary-and-noncontributory status are two different changes to the policy. The additional insured endorsement puts the contractor into “Who Is An Insured.” The 2013 edition, CG 20 10 04 13, covers the contractor only for injury or damage “caused, in whole or in part” by your acts or omissions, or those of people acting on your behalf, during your ongoing operations, says nothing about which policy pays first, and stops once the work is complete. Completed operations take a second endorsement, CG 20 37.
The 2013 edition also ties what the additional insured gets to the contract: coverage applies “to the extent permitted by law,” “will not be broader than” what the contract requires, and is capped at the lesser of the contract’s limit and your declarations. The “permitted by law” piece varies by state; IRMI’s commentary on the 2013 forms named California, Colorado, Kansas, Montana, New Mexico, Oregon and Texas as states whose anti-indemnity statutes bar an additional insured from getting more through insurance than through indemnification.
A certificate can’t fix any of this. Sonoma County’s contract guide says certificate wording about additional insured or primary and noncontributory status is not binding; it has to be endorsed to, or included in, the policy. What a certificate does and doesn’t do, and how additional insured endorsements work on a contractor policy.
What to ask your broker
- Send the contract’s insurance section, not a summary. CG 20 01 keys off what you agreed to in writing, and the 2013 additional insured forms cap coverage at what the contract requires.
- Get copies of the endorsements, not just the certificate. Oregon DOT requires the additional insured endorsements with the certificate; New York OGS sets its own deadline for them. If they can’t be produced, the wording may not be on the policy.
- Ask which forms. CG 20 10 for ongoing operations, CG 20 37 for completed operations, CG 20 01 or equivalent wording for primary and noncontributory. With a blanket additional insured endorsement, ask whether primary and noncontributory wording is built in or needs its own page.
- Ask about the umbrella and the auto policy. Both agencies require umbrella or excess policies to follow form and all liability policies, not just general liability, to be primary and noncontributory. Auto takes its own additional insured endorsement; New York OGS names CA 20 48.
- Check for a waiver of subrogation. New York OGS asks for one alongside the primary and noncontributory wording. It is a separate endorsement.
I read this wording against the carrier’s forms before the job starts. General liability for contractors and other businesses.
Common questions
Is being an additional insured the same as primary and noncontributory?
No. An additional insured endorsement adds the other party to Who Is An Insured for claims tied to your work; primary and noncontributory changes the Other Insurance condition so your policy pays first and won’t ask the other party’s policy to share. The contracts I see ask for both.
My certificate says “primary and noncontributory.” Isn’t that enough?
No, a certificate is information only. Sonoma County’s contract guide says certificate wording about additional insured or primary and noncontributory status is not binding unless it is endorsed to or included in the policy. Ask for the endorsement itself.
What is ISO CG 20 01?
A one-page ISO endorsement, edition 04 13, titled Primary and Noncontributory – Other Insurance Condition. It makes the policy primary to, and bars contribution from, other insurance available to an additional insured, provided the additional insured is a named insured on that other policy and you agreed to primary and noncontributory in writing.
Does primary and noncontributory cover completed operations?
CG 20 01 attaches to both the general liability and the products/completed operations coverage parts, but it only works for someone who is an additional insured. Ongoing-operations status under CG 20 10 ends when the work is done, so completed operations status needs CG 20 37 or an equivalent as well.
Does it apply to my auto and umbrella policies too?
CG 20 01 is a general liability endorsement. Contracts from agencies such as New York OGS and Oregon DOT require every liability policy to be primary and noncontributory and the umbrella to follow form, and auto needs its own additional insured endorsement. Ask the broker to check each policy, not just the GL.
Sources
- ISO CG 20 01 04 13, Primary and Noncontributory – Other Insurance Condition: endorsement text, coverage parts and its two conditions (Missouri Farm Bureau Insurance form library)
- ISO CG 20 10 04 13, Additional Insured – Owners, Lessees or Contractors – Scheduled Person or Organization: ongoing-operations wording, 2013 limits, no other-insurance clause (City of Yorba Linda copy)
- IRMI glossary: definition of primary and noncontributory
- IRMI (Craig Stanovich): Other Insurance and the CGL Policy, on primary as the default, excess when an additional insured elsewhere, sharing methods and the self-insurance court opinion
- IRMI (Mark Bell): 2013 ISO additional insured endorsements, the three 2013 restrictions and the anti-indemnity state list
- County of Sonoma contract insurance guide: additional insured endorsements, primary and non-contributory coverage, shared defense costs and self-insured retention
- County of Sonoma contract insurance guide: certificates are information only and do not create coverage
- New York State OGS, RFP 23062 Attachment 9: primary and non-contributory clause, additional insured forms, blanket endorsement, endorsement timelines, waiver of subrogation, umbrella follow-form
- Oregon DOT, Exhibit F: subcontractor insurance requirements, primary and noncontributory with self-insurance, endorsements with the certificate, umbrella follow-form
General information about primary and noncontributory wording and ISO general liability endorsements as of October 2026, not legal advice; the policy and endorsements actually issued, the contract and state law control. Coverage depends on underwriting and the terms, conditions and exclusions of the policy actually issued.