What's the difference between a certificate of insurance and an additional insured endorsement?

A certificate of insurance (COI) is a one-page proof-of-coverage snapshot that describes your coverage on a given date. It creates no coverage by itself. An additional insured endorsement is a form your carrier attaches to your GL policy that actually extends coverage to a named third party (the GC) for liability arising from your work.

What are CG 20 10 and CG 20 37?

CG 20 10 is the additional insured endorsement form for ongoing operations. CG 20 37 covers products and completed operations. Many GCs require both forms to be attached to your policy.

How long does it take to get an additional insured endorsement?

A broker can often produce a clean, matching COI plus endorsement package in 1 to 3 business days from the time you submit the request.

What is primary and non-contributory wording?

Primary and non-contributory language means your insurance pays first and does not share costs with the GC's insurance if a claim arises from your work. This is a common requirement in GC insurance exhibits.

Can I sign the contract with just a certificate of insurance?

No. A certificate of insurance alone does not satisfy an additional insured requirement. You must have your carrier issue the actual endorsement form (CG 20 10 or CG 20 37) and ensure it matches the GC's exhibit before signing.

CG 20 10 is a standard ISO additional insured endorsement that extends your general liability coverage to a named third party — typically the general contractor — for liability arising out of your ongoing operations. Post-2004 editions generally exclude completed operations, which is why many GC exhibits also require CG 20 37. Always match the exact edition date named in the exhibit.

CG 20 37 is the standard ISO additional insured endorsement covering products-completed operations — liability arising from your work after the project is finished. GCs often require both CG 20 10 and CG 20 37 to cover ongoing and completed work.

Can I sign with a COI alone?

No. A certificate of insurance (ACORD 25) only describes coverage on a given date and, per its own fine print, grants no coverage. When a GC requires additional insured status, you need your carrier to issue the actual endorsement form. Do not sign the exhibit until the endorsement forms match the GC's template exactly.

Additional Insured Endorsement: GC Requirements

Additional insured endorsement: what CG 20 10 and CG 20 37 do, why a certificate alone is not enough, and what GCs actually need before you sign.

This content is general information only and is not legal, tax, financial or insurance advice. Speak to an appropriately licensed professional before acting on it.

🎯 When a GC wants you added as additional insured before you can sign, you cannot satisfy that with a certificate of insurance alone. You need your carrier to issue an additional insured endorsement (usually CG 20 10 for ongoing work and CG 20 37 for completed operations), plus primary and non-contributory wording and often a waiver of subrogation. The COI is proof the endorsement exists; the endorsement is the coverage. Allow one to three business days, and do not sign until the endorsement forms match the exhibit.

Last updated: August 2026.

Methodology: This guide compares endorsement requirements against the standard ISO/ACORD forms named in typical GC insurance exhibits, ranked by fit for a licensed subcontractor. It relies on published carrier form specifications, ACORD certificate language, and state insurance-department guidance, all cited below. No product is being sold here; the goal is to tell you whether you can sign.

TL;DR

The GC is asking for an endorsement, not a certificate. A COI naming them as "certificate holder" is not the same as an additional insured endorsement, and payment holdups often trace back to this exact confusion.
The two forms most exhibits demand: CG 20 10 (ongoing operations) and CG 20 37 (completed operations). Many GCs require both.
Turnaround for a clean, matching COI + endorsement package is typically 1 to 3 business days; ask your broker whether the insurer charges for the endorsement.
The three answers to "can I sign this?" are: you can sign · you can sign once you fix these two things · don't sign yet. This workflow tells you which.

What "add me as additional insured before you sign" actually means

The general contractor is telling you their insurance-requirements exhibit demands that their entity be covered under your general liability policy, so that if a claim arises from your work, your carrier defends and pays first.

That protection only exists when your insurer attaches an additional insured endorsement to your policy. A certificate of insurance (COI) is a snapshot that describes your coverage on a given date. It creates no coverage by itself, and the fine print on the ACORD 25 form says exactly that.

Definition box

Additional insured endorsement: a form your carrier attaches to your GL policy that extends coverage to a named third party (the GC) for liability arising from your work. Common forms: CG 20 10 (ongoing operations) and CG 20 37 (products-completed operations).
Certificate of insurance (COI): a one-page proof-of-coverage summary (ACORD 25). It evidences the endorsement; it does not grant coverage.
Certificate holder: the party the COI is issued to. Being a certificate holder is not the same as being an additional insured.

This distinction comes from the policy forms rather than from state law, though any one policy can change it. The parts that clearly vary by state are licensing and workers' comp thresholds, covered lower down.

The workflow: from exhibit landing to a COI the portal accepts

Ranked by fit for a licensed subcontractor answering a GC's additional insured requirement, work through these steps in order.

Read the exhibit and list the exact forms named. Look for the specific edition dates (e.g., "CG 20 10 04 13" and "CG 20 37 04 13"), the primary-and-non-contributory requirement, and any waiver of subrogation demand. Copy the form numbers verbatim — edition dates matter, because a 1985 CG 20 10 grants completed-operations coverage while post-2004 editions do not, which is precisely why many exhibits also require CG 20 37.
Send the exhibit — not just a description — to your broker. Your broker needs the actual pages to match forms exactly. Ask them to confirm your carrier can issue each named form at the named edition date.
Confirm the endorsement is issued, then request the COI. The endorsement is the coverage; the COI is the receipt. Do not accept a COI that lists the GC only as "certificate holder" when the exhibit asks for additional insured status.
Match every line to the exhibit before signing. Compare form numbers, edition dates, primary/non-contributory language, and waiver of subrogation against the GC's template side by side.
Upload to the compliance portal (a payment or compliance portal, or the GC's own system) and resolve any auto-flags. Portals frequently reject on edition-date or wording mismatches that a human would wave through, so expect one revision cycle.

⚠️ Honesty checkpoint: Do not sign the exhibit until your carrier's endorsement forms — including form number, edition date, primary-and-non-contributory wording, and any waiver of subrogation — match the GC's template exactly. A mismatch can leave the GC unnamed or the coverage narrower than promised, which voids the protection you agreed to provide and exposes you to a defense-cost clawback.

Ask your broker about fees

Whether an insurer charges for an additional insured endorsement depends on the insurer and the policy. Some policies already include a blanket additional insured endorsement; others need a form added for the project. Ask your broker before you commit to a bid or sign an exhibit.

What varies by state

The policy forms above cover the coverage concepts. Two things genuinely change by jurisdiction:

Licensing. Whether your trade requires a state or local contractor license, and at what threshold, is set by each state. Check your state contractor licensing board.
Workers' compensation thresholds. The employee count that triggers mandatory workers' comp coverage — and how sole proprietors and officers may opt in or out — varies by state. NCCI publishes the underlying rating rules in most states; a handful (California, New York, and others) run their own systems.

External authority references

National Association of Insurance Commissioners — consumer guidance on certificates of insurance and endorsements: naic.org (accessed August 2026).
NCCI — endorsement and classification rules, workers' compensation basics: ncci.com (accessed August 2026).

Verify form availability with your own broker; the sources above explain the concepts, not your specific policy.