Primary and non-contributory: what risk managers need to know
If additional insured status is the right to coverage, primary and non-contributory is the order of payment. The risk-transfer math doesn't work without it.
The plain-English version
When two insurance policies cover the same loss, normally they share the cost ("contribute") according to their share of total limits. That's how a typical commercial loss with multiple insureds gets paid: the carriers split it.
In a vendor relationship, you don't want that. The whole point of requiring the vendor to insure your firm is so the vendor's carrier carries the risk. If your own carrier ends up paying half because of contribution, you've done all the contract work and gotten only half the protection.
Primary and non-contributory says: the named insured's policy is the only one paying until its limits are exhausted. Your policy doesn't even come into the picture until then.
The endorsement
The standard ISO endorsement is CG 20 01 04 13(Primary and Noncontributory — Other Insurance Condition). On a COI, the language typically reads something like:
Coverage is Primary and Non-Contributory per CG 20 01 in favor of [Certificate Holder] where required by written contract.
Like with additional-insured status, the COI is informational — the binding document is the endorsement on the policy. For high-stakes work, request a copy of the CG 20 01 from the broker.
Don't accept vague 'primary' language.
COIverify extracts the Description of Operations box, detects primary-and-non-contributory references, and flags certs without explicit CG 20 01 references.
Common failure modes
- Additional insured is present, primary and non-contributory is not.You're covered, but your insurer still ends up contributing. Half-protection.
- Cert says "primary" without the non-contributory piece."Primary" alone may still allow contribution from your policy. Both words need to be there for the right effect.
- Conditional language only triggers on contracts that were never executed.If the language says "where required by written contract" but the contract was never signed, the conditional language doesn't apply. Pair the requirement with a signed contract on file.
What contracts should require
A contract that takes risk transfer seriously will require all three together:
- Additional insured (CG 20 10 + CG 20 37)
- Primary and non-contributory (CG 20 01)
- Waiver of subrogation (CG 24 04 / WC 00 03 13)
Each one closes a different gap. Skip any of them and the risk-transfer math leaks.
Frequently asked questions
What does primary and non-contributory mean?
Primary and non-contributory is a coverage endorsement (typically CG 20 01 on commercial general liability) that says the named insured's policy will respond as primary insurance for a claim, and will not seek contribution from the additional insured's own policy. It puts the vendor's insurer on the hook first.
Why does it matter?
Without it, when a claim hits, both the vendor's policy and your policy could be 'on the risk,' and the insurers may share defense and indemnity costs (contribution). That's bad for two reasons: your loss history takes a hit, and your deductible may apply. Primary and non-contributory keeps your policy out of the picture entirely until the vendor's limits are exhausted.
How is it different from additional insured status?
Additional insured gives you coverage rights under the vendor's policy. Primary and non-contributory determines the order in which the policies pay. You typically want both: additional insured to be covered, and primary and non-contributory to make sure the vendor's coverage answers first.
Where does it appear on a COI?
In the 'Description of Operations / Locations / Vehicles' box. Look for explicit text like 'Coverage is primary and non-contributory per CG 20 01 where required by written contract.' Vague language without an endorsement reference is weaker.
Related reading
Additional insured: what it means and how to verify it
Adding another party to a policy so they're covered too — and the language to look for to confirm it's actually been done.
ReadWhat is a waiver of subrogation?
A contract clause where the insurer gives up its right to recover damages from a third party. What it means in practice for COI verification.
ReadWhat is a certificate of insurance (COI)?
A one-page summary issued by an insurance carrier proving a policyholder has active coverage — and the practical guide to verifying one.
Read