Additional insured (AI) status is how risk moves down the contract chain through insurance. A subcontract typically requires the sub to name the GC, the owner and others as additional insureds on the sub’s general liability policy. If an injured worker sues the GC over something arising from the sub’s work, the sub’s insurer defends and pays, not the GC’s.
The details live in the endorsement, not the certificate. Common ISO forms:
- CG 20 10: covers the additional insured for ongoing operations.
- CG 20 37: covers completed operations, which matters for defect and injury claims after the job is done.
- Blanket endorsements: automatically add anyone the named insured agreed in writing to add.
Endorsement wording varies. Coverage may be limited to liability “caused, in whole or in part” by the named insured’s acts, and some states limit what can be shifted. Contracts often also require the coverage to be primary and non-contributory, so the sub’s policy pays first.
Why it matters
Contract indemnity is only as good as the indemnitor’s ability to pay. Additional insured status puts an insurance company behind the promise. Without it, the GC’s own policy pays claims that should have been the sub’s.
Common mistakes
- Relying on a certificate that says “additional insured” without the endorsement.
- Getting ongoing operations coverage but not completed operations.
- Not requiring primary and non-contributory wording.
- Missing the owner or lender from the list of additional insureds.
How os.construction handles it
We’re building compliance records that keep insurance requirements on each subcontract and track the endorsements received against them. It’s in development.