When he is listed as the certificate holder, your client is ensured that your insurance policy that valid. A certificate holder’s only right is to receive notification if the policyholder changes or cancels his policy. He does not have any coverage under the policy and cannot make a claim on your policy. Your client can feel sure that you have coverage and that he will be informed if you cancel the policy for any reason.
An additional insured, on the other hand, does have legal rights under your policy and can make a claim on it. If a claim is made against another contractor that is listed as additional insured on your policy, he can make a claim on your policy. However, unlike a certificate holder, an additional insured won’t be informed of any changes to your policy.
A client or contractor can be both a certificate holder and additional insured, which would give them a full set of rights. They would be covered by your policy, as well as being notified to any changes or cancellation.