A blanket additional insured endorsement extends additional insured status automatically to any party the named insured has agreed in a written contract to add, rather than requiring each one to be scheduled by name. It is triggered by the existence of the contractual obligation, which means the written agreement has to actually require it.
Updated September 2026.
Why brokers care
Blanket wording is convenient and frequently misread. Because nobody is named, teams assume the requirement is satisfied, but the endorsement only reaches parties the insured was contractually obliged to add and only to the extent the contract requires. If the written agreement is silent, or was never signed, the blanket wording may extend nothing at all. The certificate will look the same either way.
What to check
- That a signed written contract exists requiring the additional insured status
- Whether the blanket wording is limited to ongoing operations
- Any requirement in the contract for a scheduled endorsement instead
- Whether the blanket form's coverage matches what the contract demands
- That the contract predates the loss, since some forms require it
Common mistake
Assuming blanket means automatic. It reaches only parties the insured was contractually obliged to add, so an unsigned or silent agreement can leave it extending nothing. Where a contract is still in negotiation, the blanket wording is not yet doing anything.
Work through it against the full certificate review checklist.