What's the difference between an Additional Insured and a Certificate of Insurance?

Most general contractors will request to be added to the liability insurance policy of a subcontractor as an additional insured. Why?

The typical additional insured endorsement will provide some defense and indemnity to the party named as an additional insured. If a subcontractor causes bodily injury or property damage while working for a general contractor, the general will want access to the protection afforded under the subcontractors insurance policy against claims made by the injured /damaged party. This endorsement is intended to accomplish this.

Warning: Not all additional insured endorsements are alike. In recent years many insurers are limiting the protection afforded under this endorsement. Discuss with your insurance consultant.

A certificate of insurance is nothing more than a piece of paper that shows the name/company insured, the policy number, the policy effective date, and the limits of coverage as of the day the certificate was issued.