Your certificate of insurance (COI) does not count as an additional insured endorsement because a COI is a summary snapshot, not a contract. The COI is issued "for information only" and, per its own printed language, confers no rights and amends no policy. The additional insured endorsement (typically a CG 20 10 for ongoing work and a CG 20 37 for completed operations) is the actual policy form that grants the GC coverage. A GC that wants proof of additional insured status, not just a COI, is asking for the endorsement pages, and 100% of the legal weight lives in those pages, not in the certificate.
Last updated: August 2026. Pricing verified August 2026 — changes often; verify before committing.
TL;DR
- A COI is issued on an ACORD 25 form that states in its own header it is "for information only" and grants zero rights — it is not the coverage.
- The additional insured endorsement (CG 20 10, CG 20 37) is the endorsement form attached to your general liability policy that actually names the GC as an additional insured.
- A GC withholding payment "pending a COI" almost always means they also need the endorsement schedule and the primary and non-contributory language attached — a bare ACORD 25 gets rejected in most compliance portals.
- This distinction is national and identical in every state. The mechanics of a COI vs endorsement do not change from California to Texas to New York.
What is the difference between a COI and an additional insured endorsement?
The difference is that a certificate of insurance describes coverage and an endorsement changes coverage. Only one of those actually protects the general contractor.
A certificate of insurance (COI) is the one-page ACORD 25 your broker emails you. It lists your carrier, your policy numbers, your limits, and your dates. Read the box at the top: it says the certificate is issued "as a matter of information only" and "confers no rights upon the certificate holder." That sentence is why a COI, by itself, does not make anyone an additional insured. It is a receipt, not the transaction.
An additional insured endorsement is a form attached to your general liability policy that amends who counts as an insured. The two forms a GC almost always wants are the CG 20 10 (additional insured for ongoing operations) and the CG 20 37 (additional insured for completed operations, the coverage that survives after you leave the site). When those forms name the GC or list "any person or organization you are required by written contract to add," the GC actually has coverage under your policy. That is the document with legal effect.
Definition — Additional insured endorsement: A policy form (commonly CG 20 10 for ongoing work and CG 20 37 for completed operations) that extends your general liability coverage to a third party such as a general contractor. Unlike a COI, the endorsement is part of the contract of insurance and can be enforced against your carrier. The COI merely reports that such an endorsement may exist; the endorsement pages themselves are what a court, a claims adjuster, and a compliance reviewer will actually read to determine coverage. If the endorsement is not attached to the policy, the third party is not covered — regardless of what the certificate says.
Why does the ACORD 25 carry no legal weight?
The ACORD 25 is a standardized industry form published by ACORD (the Association for Cooperative Operations Research and Development). Its disclaimer language is deliberate: the certificate "does not affirmatively or negatively amend, extend or alter the coverage afforded by the policies." In plain terms, the form is designed to summarize, never to grant. Multiple state insurance regulators have codified this by prohibiting certificates from being used to alter policy terms — see the National Association of Insurance Commissioners (NAIC) model act on certificates of insurance, which most states have adopted in some form.
The ISO/NCCI form families themselves define what each endorsement does. The CG 20 10 and CG 20 37 are ISO commercial general liability forms; their scope and edition dates matter, because an older CG 20 10 edition may exclude completed operations entirely. See the ISO commercial lines form catalog and the NCCI resource library for how these standardized forms and their edition dates are maintained and interpreted.
Courts have repeatedly reinforced the same hierarchy: the policy and its endorsements control, and a certificate cannot create coverage the policy does not provide. For a representative treatment of certificate-versus-endorsement enforceability, see the International Risk Management Institute (IRMI) analysis of certificates of insurance and additional insured status, which surveys the case law establishing that a COI holder generally cannot sue on the certificate itself.
Is the COI vs endorsement distinction really the same in every state?
Yes. Because the ACORD 25 is a national form and the CG 20 10 / CG 20 37 are national ISO forms, the underlying mechanics do not change at a state border. What can vary is the exact statutory language regulating certificate misuse and any state-specific broker penalties — but the core rule (certificate describes, endorsement grants) is uniform. Attorneys tracking this across jurisdictions confirm the consistency; the IRMI multi-state certificate-of-insurance guidance walks through how the same principles apply from California to Texas to New York.
What should you actually send the GC?
Send three things, not one:
- The ACORD 25 (the summary they filed request against).
- The additional insured endorsement pages (CG 20 10 and/or CG 20 37, correct edition dates), showing the GC named or covered by blanket wording.
- Any primary and non-contributory and waiver of subrogation endorsements the contract requires.
A bare ACORD 25 gets rejected in most compliance portals precisely because reviewers know it is "information only." The endorsement pages are the deliverable that ends the dispute.
Methodology: This guide is based on the published text of the ACORD 25 certificate form, the ISO CG 20 10 and CG 20 37 endorsement forms, NAIC and state-level certificate-of-insurance model acts, and secondary legal analysis from IRMI. Form scope depends on edition date; verify the specific edition attached to your policy before relying on it. Pricing and availability change often — verify before committing.