Written by Justin Goodman, CIC, CRIS, CCIP, CEO and Co-Founder, Total CSR Published: August 26, 2026 · Last reviewed: August 26, 2026
In plain language: CG 20 37 adds a project owner, developer, or general contractor as an additional insured on a contractor’s general liability policy for lawsuits arising after the contractor’s work is finished, such as a defect that causes injury or damage years later.
Technical definition: CG 20 37 is an ISO CGL endorsement that grants additional insured status to a scheduled party for liability arising out of the named insured’s completed operations, as defined in the policy’s completed operations hazard, without requiring a written contract provision at the time of the occurrence.
CG 20 37 Endorsement at a Glance
| Attribute | Detail |
|---|---|
| Also known as | Additional Insured – Owners, Lessees or Contractors – Completed Operations |
| Category | Additional insured endorsement |
| Lines of business | Commercial General Liability |
| Industries most affected | Construction, general contracting, subcontracting trades, real estate development |
| Related forms or endorsements | CG 20 10 (ongoing operations AI), CG 20 33 (automatic status with contract), CG 20 38 (ongoing and completed ops combined) |
| Who bears the risk | Subcontractor or contractor named on the endorsement schedule (as the party extending coverage) |
| Common solution | Pairing CG 20 37 with CG 20 10 or CG 20 33 to cover both active work and post-completion claims |
| Also interacts with | Certificates of insurance, indemnification clauses, primary and noncontributory endorsements |
Key Takeaways
- CG 20 37 extends additional insured status to an owner or general contractor for bodily injury or property damage claims tied to a subcontractor’s completed work.
- Agencies rely on this endorsement to satisfy construction contract requirements that demand coverage surviving project completion, often for years after the certificate of insurance was issued.
- The most common pitfall is assuming CG 20 10 alone covers post-completion claims; standard CG 20 10 excludes completed operations, so a separate CG 20 37 or a combined form is required.
- Agencies should confirm the endorsement is scheduled to the correct project or blanket basis and matches the contract’s duration requirement before issuing a certificate.
What Is CG 20 37 Endorsement in Insurance?
CG 20 37 is the ISO endorsement that adds an owner, developer, or general contractor as an additional insured on a subcontractor’s CGL policy specifically for liability tied to completed operations. The provision exists because construction defect and injury claims often surface long after a job wraps up, when the contractor’s active-operations coverage under CG 20 10 no longer applies. Carriers use this endorsement to define precisely how long, and for what, the additional insured’s protection extends past substantial completion.
The doctrine behind this form traces to the “completed operations hazard” definition found in the CGL policy itself. Once work is finished, put to its intended use, and accepted by the owner, any resulting injury or damage falls into a different coverage bucket than ongoing operations. A general contractor who never secures CG 20 37 from its subcontractors may find itself uninsured for claims filed years after a project closes, even if it held perfectly valid coverage during construction.
Consider a roofing subcontractor that finishes a commercial building in 2022. In 2026, the roof fails during a storm, causing water damage and a lawsuit naming both the roofer and the general contractor. If the roofer’s policy included CG 20 37 naming the general contractor as an additional insured for completed operations, the general contractor can tender the claim to the roofer’s carrier instead of relying solely on its own policy or an expired certificate.
How Does CG 20 37 Endorsement Work?
- The contract requirement. A construction contract or subcontract requires the subcontractor to name the owner or general contractor as an additional insured for completed operations, often for a specified number of years after project completion.
- The endorsement issuance. The subcontractor’s CGL carrier issues CG 20 37, scheduling the additional insured and the covered project, either on a per-project or blanket basis.
- The certificate delivery. The agency issues a certificate of insurance reflecting the additional insured status, though the certificate itself creates no coverage and merely evidences the endorsement’s existence.
- The post-completion loss. A claim arises after the subcontractor’s work is finished and accepted, falling within the completed operations hazard definition.
- The tender and response. The additional insured tenders the claim to the subcontractor’s carrier under CG 20 37, and the carrier evaluates whether the loss arose out of the named insured’s completed operations before accepting or denying coverage.
Real Claim Examples Involving CG 20 37 Endorsement
Roof Collapse Two Years After Substantial Completion
A general contractor hired a structural subcontractor to install roof trusses on a warehouse. Two years after completion, a section of the roof collapsed under snow load, injuring a warehouse employee. Because the subcontractor’s policy carried CG 20 37 naming the general contractor as an additional insured for completed operations, the general contractor’s defense costs and indemnity exposure were picked up by the subcontractor’s carrier rather than its own policy.
Faulty Electrical Work Discovered During a Property Sale
An electrical subcontractor completed wiring on a retail buildout in 2023. During a 2026 due diligence inspection ahead of a property sale, an inspector found code violations that had caused intermittent arcing damage to inventory. The property owner, named as an additional insured under CG 20 37 in the subcontractor’s policy, tendered the claim, and coverage applied because the damage arose from completed operations performed by the named insured.
Certificate Without the Matching Endorsement
A general contractor received a certificate of insurance showing additional insured status but the subcontractor’s policy only carried CG 20 10 for ongoing operations, with no completed operations endorsement attached. When a slip-and-fall claim arose from a walkway installed by the subcontractor eighteen months after project completion, the subcontractor’s carrier denied additional insured coverage to the general contractor because CG 20 37 had never actually been issued, despite the certificate’s language.
CG 20 37 Endorsement vs. CG 20 10: What Is the Difference?
CG 20 37 and CG 20 10 both grant additional insured status under a CGL policy, but they apply to different phases of a construction project. CG 20 10 (in its current edition) covers liability arising from the named insured’s ongoing operations performed for the additional insured, while CG 20 37 covers liability arising from the named insured’s completed operations after the work is finished.
| Comparison area | CG 20 37 Endorsement | CG 20 10 Endorsement |
|---|---|---|
| Primary use case | Post-completion claims from finished work | Claims arising while work is still in progress |
| Coverage / concept type | Completed operations additional insured status | Ongoing operations additional insured status |
| Typical exclusions | Claims unrelated to the named insured’s own completed work | Completed operations, on current ISO editions, unless combined with CG 20 37 |
| Who is most affected by errors | General contractors and owners relying on subcontractor coverage after project closeout | General contractors relying on subcontractor coverage during active construction |
| Common mistakes | Assuming CG 20 10 alone covers claims after project completion | Assuming the ongoing operations endorsement extends automatically once work ends |
What Are the Most Common Mistakes With CG 20 37 Endorsement?
- Agencies issue certificates showing additional insured status without confirming CG 20 37 was actually attached to the policy, creating an E&O gap when a post-completion claim is denied.
- Producers assume CG 20 10 alone satisfies a contract’s completed operations requirement, leaving the additional insured uncovered once the project is finished.
- Agencies fail to track the duration language in the underlying contract, which may require coverage for several years after completion, exceeding what a single policy term or blanket endorsement provides.
- CSRs schedule the wrong project or omit the project description on the endorsement, leaving the additional insured unprotected for the specific job that generated the claim.
- Agencies overlook that CG 20 37 does not cover the additional insured’s own negligence, only liability arising out of the named insured’s completed operations.
How to Explain CG 20 37 Endorsement to a Client
Explaining CG 20 37 Endorsement to a personal lines client
This endorsement generally does not apply to personal lines, since it lives in commercial general liability policies tied to construction contracts. If a homeowner client asks about it, this is a good moment to explain that it protects businesses, like a general contractor, from lawsuits over a subcontractor’s finished work rather than covering personal property or home repairs.
Explaining CG 20 37 Endorsement to a small business owner
This endorsement adds you as an additional insured on your subcontractor’s policy so that if something goes wrong with their finished work after the job is done, their insurance responds first. It matters because your own policy might not be enough if a defect surfaces years later. We want to make sure every sub on your jobs carries this, not just proof of insurance during construction.
Explaining CG 20 37 Endorsement to a CFO or risk manager
CG 20 37 shifts completed operations liability to the subcontractor’s carrier through additional insured status, which is distinct from the ongoing operations coverage under CG 20 10. We recommend verifying the actual endorsement, not just the certificate, and confirming the duration matches your contractual indemnification period. We can also review whether a combined form or blanket additional insured endorsement better fits your risk transfer strategy across multiple subcontractors.
Frequently Asked Questions About CG 20 37 Endorsement
What does CG 20 37 actually cover?
CG 20 37 covers bodily injury or property damage claims that arise out of the named insured’s completed operations, once work is finished and accepted, naming a scheduled owner, developer, or general contractor as an additional insured. It does not cover claims arising from the additional insured’s own independent negligence or from operations unrelated to the named insured’s scope of work.
Does a certificate of insurance prove CG 20 37 is in place?
A certificate of insurance does not create coverage and only reflects what the agency believes is on the policy at the time it was issued. Agencies should request a copy of the actual endorsement or policy language to confirm CG 20 37 was issued, since certificates have been the subject of numerous E&O claims when coverage did not match what was represented.
How long does CG 20 37 coverage last after a project ends?
Coverage duration depends on the underlying CGL policy’s completed operations hazard definition and how long the additional insured status endorsement remains attached to active policies, not a fixed statutory period. Many construction contracts require the additional insured status to continue for several years after completion, so agencies should track renewal continuity for named subcontractors on long-tail projects.
Can CG 20 37 and CG 20 10 be combined into one endorsement?
Yes, ISO offers combined forms such as CG 20 38, which grants additional insured status for both ongoing and completed operations in a single endorsement. Agencies often prefer the combined form when a contract requires continuous additional insured status across both phases of a project.
Who is the named insured under CG 20 37, and who is the additional insured?
The named insured is typically the subcontractor or contractor whose policy the endorsement is attached to, and the additional insured is the owner, developer, or general contractor scheduled on the endorsement. The named insured’s completed operations generate the coverage trigger, while the additional insured receives the protection.
Does CG 20 37 satisfy every construction contract’s insurance requirement?
Not automatically. Contract language often specifies duration, scope, and whether coverage must be primary and noncontributory, so agencies must compare the endorsement’s actual terms against the contract rather than assuming a generic CG 20 37 satisfies every clause. Total CSR’s training work with agencies consistently shows that CSRs who compare endorsement wording line by line against contract insurance requirements catch far more gaps than those who rely on certificate templates alone.
Related Insurance Terms
- CG 20 10 Endorsement: An ISO additional insured endorsement covering liability arising from a contractor’s ongoing operations, distinct from CG 20 37’s focus on completed work.
- Completed Operations Hazard: The CGL policy definition marking when work is considered finished, triggering the shift from ongoing operations coverage to completed operations coverage.
- Additional Insured Endorsement: A broad category of CGL modifications that extend liability protection to a party other than the named insured, of which CG 20 37 is one specific type.
- Primary and Noncontributory Endorsement: A separate endorsement often required alongside CG 20 37 to ensure the additional insured’s coverage responds first, without seeking contribution from the additional insured’s own policy.
- Certificate of Insurance: A document summarizing policy coverage that does not by itself grant additional insured status, making verification of the underlying CG 20 37 endorsement essential.
- Indemnification Clause: A contract provision requiring one party to cover another’s losses, frequently paired with additional insured requirements like CG 20 37 to accomplish full risk transfer.
Sources and References
- Insurance Services Office (ISO), via Verisk. ISO forms and endorsements information.
- International Risk Management Institute (IRMI). Additional Insured Endorsements: A Primer.
About the Author
Justin Goodman, CIC, CCIP, CISC, CLCS, CRIS, PCIA, QCLS, MFHR CEO and Co-Founder, Total CSR, Inc.
Justin Goodman is a third-generation insurance broker with over two decades in agency operations. He has trained more than 50,000 CSRs, account managers, and producers in commercial and personal lines coverage, from workers’ compensation to construction risk. He was named 2024 Insurance Journal Agent of the Year and one of the nation’s top five construction insurance experts by Risk & Insurance. He is the author of Retain, which applies cognitive science research on memory and knowledge transfer to insurance training, and speaks nationally on how agencies build durable technical expertise in their teams.