Glossary
Additional insured
An additional insured is a person or business added to someone else's insurance policy by endorsement, giving them coverage for liability arising out of the named insured's work or operations. It is standard in construction and service contracts: the hiring party wants protection under the contractor's policy, not just proof the policy exists.
Scheduled vs blanket
A scheduled additional insured endorsement names each party individually. A blanket (or automatic) endorsement covers any party the named insured agrees in a written contract to add, which is why contracts usually require the agreement in writing.
On ISO commercial general liability policies, the endorsements contracts most often name are CG 20 10 for ongoing operations and CG 20 37 for completed operations. Contract insurance requirements frequently cite those form numbers, sometimes even specific editions, so match the requirement to what the carrier will actually issue.
Where agencies get burned
Additional insured status lives on the policy, not on the certificate. A certificate of insurance can only reflect an endorsement that already exists. Issuing a cert that shows additional insured status the policy does not provide is one of the most common E&O traps in agency work.
The safe order of operations: read the contract's insurance requirements, confirm or add the matching endorsement with the carrier, then issue the certificate. Premium impact varies by carrier and endorsement, so quote the change rather than promising it is free.
Common questions
What is the difference between an additional insured and a certificate holder?
A certificate holder gets proof of coverage and nothing else. An additional insured actually has coverage under the policy for liability arising out of the named insured's work.
Does adding an additional insured change the premium?
It depends on the carrier and the endorsement. Some policies include blanket additional insured wording already. Scheduled additions can carry a charge. Check with the carrier before committing.
Part of the Relay insurance operations glossary. Updated 2026-07-11. See how we source content.
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