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

The fundamental difference is temporal coverage: ISO CG 20 10 provides Additional Insured coverage strictly during the active, ongoing construction phase while work is in progress. ISO CG 20 37 provides Additional Insured coverage for the Products-Completed Operations Hazard after work has been completed, accepted, or put to its intended use.

Why was the historic CG 20 10 11 85 edition so popular among general contractors?

The November 1985 (11 85) edition of CG 20 10 used the broad phrase 'arising out of your work,' which courts consistently interpreted as providing both ongoing and completed operations coverage in a single endorsement. Modern editions (10 01 and 04 13) replaced 'your work' with 'your ongoing operations,' requiring a separate CG 20 37 endorsement for completed work.

What happens if a general contractor only receives CG 20 10 and a defect claim occurs two years later?

The subcontractor's insurance carrier will immediately deny defense and indemnity to the general contractor. Because CG 20 10 coverage terminates the moment the subcontractor completes physical work on site, post-completion defect claims (such as pipe leaks or roof collapses) require the CG 20 37 endorsement.

How did the 2004 and 2013 ISO editions alter additional insured liability standards?

The 2004 (07 04) and 2013 (04 13) editions eliminated coverage for the additional insured's sole negligence. They introduced the phrase 'caused, in whole or in part, by your acts or omissions,' restricting coverage to vicarious liability caused by the named insured subcontractor and capping coverage at contractually specified limits.

How should CG 20 10 and CG 20 37 be documented on an ACORD 25 Certificate of Insurance?

Both endorsement form numbers and edition dates must be explicitly recorded in the Description of Operations or attached endorsement schedule (e.g., 'General Liability includes Additional Insured status for ongoing and completed operations per ISO CG 20 10 04 13 and CG 20 37 04 13'). Checking the 'ADDL INSD' checkbox on ACORD 25 without verifying actual attached endorsement forms confers zero legal coverage.

What is the difference between CG 20 10 and CG 20 38?

CG 20 10 requires direct contractual privity between the named insured subcontractor and the additional insured. CG 20 38 is an automatic blanket endorsement that extends ongoing operations additional insured status to upstream parties (such as project owners or construction managers) even when privity is lacking, provided the named insured is contractually required to include them.

How long should a general contractor require completed operations coverage to remain active?

General contractors typically require subcontractors to maintain General Liability insurance with completed operations additional insured coverage (CG 20 37) for the duration of the state's statute of repose for latent construction defects, which commonly spans 6 to 10 years following substantial completion.

Can a carrier issue CG 20 37 without also issuing CG 20 10?

While technically permissible as an independent endorsement form, issuing CG 20 37 alone leaves an upstream party uninsured for accidents occurring during active construction. Construction risk management best practices require general contractors to mandate both forms simultaneously.

policyGeneral Liability & Endorsements

CG 20 10 vs. CG 20 37: Ongoing vs. Completed Operations Endorsements Explained

The definitive technical guide for commercial insurance brokers, risk managers, and claims adjusters on ISO CG 20 10 and CG 20 37 endorsements, the Products-Completed Operations Hazard, edition date legal ramifications (11 85 vs. 10 01 vs. 04 13), and ACORD 25 verification.

Published 2026-06-17•14 min read•By Insure Assist AI Commercial Lines Team

Executive Summary / Direct Answer

ISO CG 20 10 covers an Additional Insured solely for liability arising out of ongoing operations while work is actively in progress. ISO CG 20 37 extends Additional Insured status to the products-completed operations hazard after work is finished. General contractors require both endorsements to avoid post-completion latent defect coverage denial.

Section 1: Contractual Mechanics

The Temporal Divide: Why One Endorsement Leaves a Multi-Million Dollar Void

In commercial construction risk management, the distinction between active job site accidents and post-handover property damage represents the single greatest source of coverage litigation. When an upstream general contractor or property owner demands Additional Insured status on a trade subcontractor’s Commercial General Liability (CGL) policy, the scope of risk transferred is dictated entirely by temporal boundaries. The standard ISO CGL policy (CG 00 01) separates bodily injury and property damage into two distinct operational categories: ongoing operations, which occur while trade work is actively in progress, and the products-completed operations hazard, which encompasses bodily injury or property damage arising out of the contractor’s completed work once operations are abandoned, completed, or put to their intended use. A general contractor who secures only the ISO CG 20 10 endorsement is protected exclusively against active construction accidents and remains completely uninsured for structural failures, water intrusion, or electrical fires manifesting after project completion.

CG 20 10: Ongoing Operations

Applies strictly while the subcontractor is physically on-site executing work under the subcontract. The moment the subcontractor packs tools, issues a final invoice, or the project receives a Certificate of Occupancy, all defense and indemnification obligations under CG 20 10 instantly terminate.

Trigger: Occurrence occurs during active construction phase.

CG 20 37: Completed Operations

Attaches to the policy’s Products-Completed Operations Hazard aggregate limit. Protects the additional insured against claims alleging defective workmanship, structural settling, water intrusion, or systemic failures that manifest months or years following project handover.

Trigger: Property damage / injury occurs post-substantial completion.

Section 2: Legal Evolution

The Critical Evolution of ISO Edition Dates: 11 85, 10 01, and 04 13

Few insurance nuances create more contentious subcontract disputes than endorsement edition dates. To understand why modern carriers fiercely resist historic forms, one must examine how the Insurance Services Office (ISO) systematically restructured Additional Insured language across four decades of court decisions.

1. The Holy Grail: CG 20 10 11 85 (November 1985)

Ongoing + Completed Combined

The 11 85 edition stated that additional insured status applied to liability "arising out of 'your work' for that additional insured by or for you." Under the standard ISO definition, "your work" encompasses both active operations and work that has been completed. Consequently, appellate courts nationwide ruled that CG 20 10 11 85 automatically conferred completed operations protection without needing any separate endorsement.

Carrier Status: Virtually extinct. Surplus lines and standard carriers almost universally refuse to attach CG 20 10 11 85 today due to unpriced completed operations exposure, issuing proprietary forms instead (such as Travelers CG T1 00 or Markel MEGL 0009). Compare carrier forms across the market in our Commercial Endorsement Cross-Reference Guide or test lookups in the Carrier Form Decoder.

2. The Great Bifurcation: CG 20 10 10 01 (October 2001)

Creation of CG 20 37

To eliminate the unintended grant of completed operations under CG 20 10, ISO replaced the broad phrase "your work" with the restrictive phrase "your ongoing operations." Simultaneously, ISO introduced the CG 20 37 10 01 endorsement specifically to cover the products-completed operations hazard. From October 2001 onward, securing completed operations required obtaining two distinct endorsement forms.

3. Vicarious Liability & Anti-Indemnity Alignment: CG 20 10 04 13 & CG 20 37 04 13

Current Industry Standard

The April 2013 revisions introduced three crucial restrictions to both CG 20 10 and CG 20 37:

Sole Negligence Barred: Coverage is restricted to liability "caused, in whole or in part, by your acts or omissions" or the acts of those working on your behalf.
Contractual Limit Cap: Insurance provided to the additional insured will not exceed the limits required in the written subcontract agreement.
Scope of Coverage Cap: Insurance afforded to the additional insured is capped at the exact scope of coverage permitted by state anti-indemnity statutes.

Section 3: Comprehensive Comparison

Technical Comparison: CG 20 10 vs. CG 20 37 vs. CG 20 38 vs. CG 20 10 11 85

When drafting master subcontract agreements or reviewing certificates of insurance, brokers must understand the exact differences across standard ISO endorsement forms.

Endorsement Form	Operational Scope	Direct Privity Required?	Primary Risk Trigger
CG 20 10 (04 13)	Ongoing operations only while work is actively in progress	Yes (Direct contract required)	Jobsite bodily injury, active site property damage
CG 20 37 (04 13)	Products-completed operations hazard post-handover	Yes (Direct contract required)	Latent structural defects, post-completion water leaks
CG 20 38 (04 13)	Ongoing operations with automatic upstream tiers	No (Extends to upstream parties)	Multi-tiered GC / Owner / Architect indemnification
CG 20 10 11 85	Both ongoing AND completed operations combined	Yes (Under broad "your work" rule)	Comprehensive project lifecycle (Historic form)

Interactive Decision Tool

Interactive Ongoing vs. Completed Operations Coverage Evaluator

Use this interactive calculator to assess coverage sufficiency, identify potential uninsurable defect gaps, and generate exact ACORD 25 certificate schedule wording for your construction subcontracts.

Claim / Incident Occurrence Timing

Subcontractor Tier & Contractual Privity

Carrier Endorsement Edition Date

Completed Ops Mandated in Prime Subcontract?

Yes (Mandated for 3–10 Yrs)No / Omitted in Subcontract

Full Lifecycle Protection (Ongoing + Products-Completed Operations)

Fully Covered

Coverage Determination:

Requires Dual Endorsement Combo (CG 20 10 + CG 20 37)

Required Endorsements:

ISO CG 20 10 (04 13)ISO CG 20 37 (04 13)Consider CG 20 38 for Upstream Owner Protection

Legal Risk Analysis:

To protect the owner and general contractor through both the active construction phase and the 10-year statute of repose post-completion, the carrier must execute both CG 20 10 (for ongoing operations) and CG 20 37 (for products-completed operations). Attaching one without the other creates an immediate uninsurable gap.

Recommended ACORD 25 Certificate Wording:

Certificate holder is included as Additional Insured on General Liability with respect to ongoing operations (CG 20 10 04 13) and products-completed operations (CG 20 37 04 13) as required by written construction agreement.

04 13 edition enforces "caused in whole or in part" standard and caps coverage limits to the lesser of policy limits or contractually required limits.

Section 4: Risk Management & E&O

Top 5 Additional Insured Pitfalls That Trigger Denials & E&O Claims

Commercial brokers face severe Errors and Omissions (E&O) exposures when issuing certificates or advising general contractors on indemnity compliance. Below are five proven failure modes:

01
Relying solely on ACORD 25 checkboxes: Checking the certificate box confers zero legal coverage without attached endorsement forms.
02
Missing the CG 20 37 endorsement: Failing to bind completed operations leaves post-completion defect claims completely uninsured.
03
Demanding obsolete 11 85 edition dates: Specifying 11 85 causes immediate carrier rejection and delays project mobilization.
04
Omitting upstream tiers in CG 20 10: Lower-tier subcontracts fail to protect owners without the CG 20 38 form.
05
Letting completed operations lapse prematurely: Policies must be maintained throughout the entire state statute of repose.

Section 5: Claims Adjusting Protocol

How Insurance Claims Adjusters Audit Additional Insured Tenders

When a general contractor tenders a defense for an active accident or structural defect claim, carrier litigation adjusters follow a rigorous 4-step forensic checklist before issuing an acceptance or reservation of rights:

Step 1: Contractual Privity & Agreement

The adjuster inspects the prime subcontract executed prior to the loss date to verify that the named insured was expressly obligated in writing to name the tenderer as an additional insured.

Step 2: Occurrence Date vs. Substantial Completion

The adjuster checks job logs and certificate of occupancy dates. If the accident happened after completion and only CG 20 10 is attached, the tender is denied immediately.

Step 3: Sole Negligence vs. Vicarious Contribution

Under 04 13 wording, the adjuster reviews police reports, OSHA citations, and expert reports to confirm the named insured subcontractor caused the loss in whole or in part.

Step 4: Attached Form Schedule Audit

The adjuster cross-references the actual policy endorsement schedule against the ACORD 25 certificate to ensure the endorsement was legally executed and paid for.

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