What is the difference between CG 20 10 and CG 20 37?

CG 20 10 covers liability from ongoing operations (while work is in progress), while CG 20 37 covers completed operations (claims that surface after work is finished). Both endorsement forms are required to fully protect a general contractor as an additional insured on your policy.

Do I need both CG 20 10 and CG 20 37 endorsements?

Yes. CG 20 10 alone leaves you exposed the moment you demobilize from a job. Completed operations claims—the expensive construction defect suits—almost always surface after project close, making CG 20 37 essential to avoid catastrophic liability gaps.

Is a certificate of insurance the same as an endorsement?

No. A certificate of insurance evidences coverage; the endorsement form grants it. General contractors increasingly demand the actual endorsement pages attached to your policy, not just a box checked on the certificate. Without the endorsement pages, the GC has no direct claim on your coverage.

What does 'additional insured' mean for a general contractor?

When a general contractor is named as an additional insured via CG 20 10 or CG 20 37, your insurer defends and pays claims first if someone sues the GC over your work. Without these endorsements attached, the GC has no direct claim on your coverage and your subcontract exposes you to uninsured liability.

Why do edition dates matter on CG 20 10 and CG 20 37?

The edition date (e.g., 04/13) indicates which version of the form is attached. The 2004 and 2013 editions changed what 'ongoing operations' actually covers, so GCs and subs must verify they are using the same edition to ensure proper coverage alignment.

CG 20 10 and CG 20 37 for Subcontractors

CG 20 10 and CG 20 37 endorsements: protect your subcontracting business from ongoing and completed operations claims. Learn why both are required.

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.

🎯 CG 20 10 and CG 20 37 are the two ISO additional insured endorsements a general contractor almost always requires from a subcontractor: CG 20 10 covers liability arising from your ongoing operations (while the job is active), and CG 20 37 covers your completed operations (claims that surface after the work is done). You need both because a certificate of insurance alone does not grant additional insured status — only the endorsement form attached to your policy does. GCs routinely reject a subcontractor's submission when the exhibit asks for "CG 20 10 (04/13) and CG 20 37 (04/13)" but the sub sends a COI without the actual endorsement pages attached.

Last updated: August 2026. Pricing verified August 2026 — changes often; verify before committing.

TL;DR

CG 20 10 = additional insured for your ongoing operations; CG 20 37 = additional insured for your completed operations (post-job). You need both endorsement forms, not just a COI.
A certificate of insurance evidences coverage; the endorsement grants it. GCs increasingly demand the endorsement pages, not just the certificate box checked.
Watch the edition date in parentheses (e.g., 04/13). The 2004 vs 2013 editions changed what "ongoing operations" actually covers.
Completed operations claims (the roof leaks 18 months after you finish) are the ones that put you out of business without CG 20 37 attached.

Definition box

CG 20 10 and CG 20 37 are standard ISO (Insurance Services Office) general liability endorsement forms that add a named party (usually a general contractor) as an additional insured on a subcontractor's commercial general liability policy. CG 20 10 applies to liability from the subcontractor's ongoing operations. CG 20 37, the completed operations endorsement, applies to liability from work already finished. Both are attached to the policy by form number and edition date, and both must be evidenced on the certificate of insurance but granted by the endorsement itself.

This is national. What CG 20 10 and CG 20 37 mean, and the difference between evidencing coverage on a certificate and granting it by endorsement, is identical in every state. A GC in California and a GC in Texas read the same form numbers off the same exhibit.

What is CG 20 10 and CG 20 37 for subcontractors, in plain terms?

CG 20 10 and CG 20 37 are the two forms that make a general contractor an additional insured on your policy so that if someone sues the GC over your work, your insurer defends and pays first. Without them attached, the GC has no direct claim on your coverage and the subcontract you just signed exposes you.

Here is the split that trips up most subs:

CG 20 10 = ongoing operations. Covers claims arising while you are performing the work. A worker falls in the trench you dug last Tuesday; the GC gets named; your policy responds.
CG 20 37 = completed operations. Covers claims arising after your work is finished and accepted by the owner or GC. This is the coverage that catches the latent defect — the roof you installed leaks 18 months later, the wiring you ran shorts and causes a fire, the concrete you poured cracks and someone is injured. Because these claims surface long after the job closes out, CG 20 10 alone will not respond to them. Only CG 20 37, attached and in force, extends additional insured protection into the completed-operations window.

Practically, this is why GCs list both form numbers on the insurance exhibit and why sending a certificate with only CG 20 10 attached gets your submission bounced. The two forms cover two different time periods of your liability, and the GC wants protection across both.

Edition dates matter: 04/13 vs 10/01

The number in parentheses is the ISO edition date, and it is not decorative. The 2004 edition (04/04) of CG 20 10 was revised in part because earlier language was read by some courts to extend ongoing-operations coverage into completed operations — which insurers did not intend. Later editions tightened the wording so CG 20 10 clearly stops at ongoing operations, making CG 20 37 the required companion for post-completion claims.

If your subcontract exhibit specifies "CG 20 10 (04/13) and CG 20 37 (04/13)," matching the edition date matters. An older edition may grant broader or narrower coverage than the GC's contract assumes, and a mismatch can be grounds for the GC to reject your certificate. Ask your agent to confirm the exact form and edition attached to your policy, in writing.

State variations

The form numbers are national — CG 20 10 and CG 20 37 mean the same thing whether you work in Florida or Oregon. What can vary by state is the surrounding legal context: state anti-indemnity statutes limit how far a subcontractor can be required to indemnify or insure a GC for the GC's own negligence, and some states restrict "additional insured" obligations in construction contracts accordingly. The ISO form itself is uniform, but how a court in your state enforces the indemnity and insurance provisions of the subcontract may differ. Confirm your specific contract language with a construction attorney licensed in the state where the work is performed.

Certificate vs endorsement: the distinction that costs subs work

A certificate of insurance (usually the ACORD 25 form) is a snapshot. It evidences that coverage exists and that certain endorsements are attached — but the certificate box is not the grant of coverage. If a dispute arises, the insurer looks at the actual endorsement pages attached to the policy, not the certificate. This is why experienced GCs now require the endorsement pages themselves (the CG 20 10 and CG 20 37 forms) alongside the ACORD certificate. A checked box on a COI with no endorsement behind it grants nothing.

FAQ

Do I really need both CG 20 10 and CG 20 37? If your subcontract requires additional insured coverage for both ongoing and completed operations — and most do — then yes. CG 20 10 alone leaves the GC unprotected against claims that surface after your work is finished.

Is the certificate of insurance enough? No. The certificate evidences coverage; the endorsement grants it. Provide the actual endorsement pages, not just the ACORD 25.

Does the edition date really matter? Yes. Different editions of CG 20 10 cover different scopes of "ongoing operations." Match the edition your subcontract specifies, and confirm it in writing with your agent.

Are these forms the same in every state? The form numbers and language are national and standardized by ISO. State anti-indemnity statutes and court interpretations of the surrounding subcontract provisions can vary, so confirm your contract with a local construction attorney.

Methodology and verification: This guide describes standard ISO commercial general liability endorsement forms as published by the Insurance Services Office. Form numbers, edition dates, and coverage descriptions were verified against ISO form references and construction-insurance sources as of August 2026. ISO periodically revises endorsement editions and states periodically amend anti-indemnity statutes; verify the current edition attached to your specific policy with your licensed agent before relying on this summary. Last updated: August 2026.

External references (verified August 2026):

Insurance Services Office (ISO), commercial lines forms and endorsement filings — verisk.com/insurance/products/iso-forms (accessed August 2026).
International Risk Management Institute (IRMI), guidance on additional insured endorsements and completed operations — irmi.com (accessed August 2026).
National Association of Insurance Commissioners (NAIC), consumer and state insurance regulator directory — naic.org/state-insurance-departments (accessed August 2026).