Written by Justin Goodman, CIC, CRIS, CCIP, CEO and Co-Founder, Total CSR
Published: August 3, 2026 · Last reviewed: August 3, 2026
In plain language: An additional insured endorsement adds another business or person, often a client, landlord, project owner, or general contractor, onto someone else’s liability policy. That third party gets insurance protection if a lawsuit arises from the named insured’s work, without having to buy or pay for a separate policy.
Technical definition (additional insured definition): An additional insured endorsement is a form attached to a Commercial General Liability, auto, or umbrella policy that extends defense and indemnity coverage to a scheduled or blanket third party for liability arising out of the named insured’s ongoing or completed operations, premises, or products, subject to the endorsement’s specific wording and limitations.
Additional Insured Endorsement at a Glance
| Attribute | Detail |
|---|---|
| Also known as | AI endorsement, AI status, automatic additional insured |
| Category | Liability policy endorsement |
| Lines of business | Commercial General Liability, Commercial Auto, Umbrella/Excess Liability |
| Industries most affected | Construction, real estate, manufacturing, habitational property |
| Related forms or endorsements | CG 20 10 (cg2010 – ongoing operations), CG 20 37 (cg2037 – completed operations), CG 20 33 (cg2033 – blanket, with contract requirement), CG 20 26 (blanket, broad), CG 20 11 (cg 20 11), CG 20 12 (cg 20 12), CG 20 38 (cg2038) |
| Who bears the risk | First named insured’s insurance carrier extends coverage; additional insured relies on that policy’s terms and coverage limits |
| Common solution | Contract-specific endorsement matched to the written agreement, verified against a certificate of insurance |
| Also interacts with | Indemnification provisions, waiver of subrogation, primary and non-contributory wording |
Key Takeaways
- An additional insured endorsement extends someone else’s general liability policy to protect a third party from claims tied to the named insured’s operations, reducing insurance costs for upstream parties.
- Agencies rely on these endorsements constantly in construction projects and leasing, where business contracts require proof of additional insured status before work can begin.
- The most common misunderstanding is treating a certificate of insurance as proof of coverage, when only the actual endorsement attached to the policy creates the insurance protection.
- A quick win is confirming the endorsement forms match the contract’s required scope of coverage, ongoing operations versus completed operations, before issuing any certificate.
What Is Additional Insured Endorsement in Insurance?
Additional insured endorsement is a policy modification that transfers a portion of the named insured’s liability protection to a third party specified in a construction agreement or other business contracts. The provision exists because contracts, especially construction subcontracts and commercial leases, routinely require one party to protect another from lawsuits arising out of shared work or shared premises. Rather than forcing every party to carry duplicate policies and increase insurance costs, the endorsement lets risk transfer happen through the party already performing the exposed activity.
The doctrine behind this is contractual risk transfer. A general contractor who hires subcontractors wants protection if the subcontractor’s employee gets hurt and sues the general contractor for negligence tied to that sub’s work. Requiring additional insured status on the subcontractor’s CGL policy means the general contractor gets defense and indemnity from the sub’s insurance carrier, not just a promise in a contract that may be hard to enforce after a loss. This additional insured language protects upstream parties from liability risks without requiring separate vendor insurance policies.
Consider a roofing subcontractor working under a general contractor on construction projects. The construction agreement requires the roofer to name the GC as an additional insured using ISO form CG 20 10 (cg2010). A worker on the roofing crew drops a tool that causes bodily injury to a pedestrian below. The pedestrian sues both the roofer and the GC for property damage and injury. Because the GC is a scheduled additional insured under the roofer’s policy, the roofer’s insurance carrier defends the GC and pays covered damages up to the roofer’s coverage limits, protecting the GC’s own policy from the loss.
Total CSR’s training work with agency staff consistently shows that CSRs who process certificates without checking the actual endorsement forms and additional insured language are the leading cause of additional insured E&O claims, not the underwriters who draft the policy declarations.
How Does Additional Insured Endorsement Work?
- The contract requirement. A written agreement, such as a construction agreement or commercial lease, requires one party to add the other as an additional insured on a specified line of coverage. These insurance requirements may also include a governmental agency, project owner, or other upstream parties depending on the nature of contractor relationships.
- The endorsement request. The named insured’s agent selects and attaches the correct ISO endorsements or proprietary endorsements form matching the contract’s scope of coverage, ongoing operations, completed operations, or both. Common forms include cg2010, cg2037, cg2033, cg2038, cg 20 11, and cg 20 12.
- The certificate issuance. The agency issues a certificate of insurance reflecting the additional insured status and compliance monitoring requirements, though the certificate itself is not the source of coverage.
- The triggering loss. A third party suffers bodily injury or property damage in a way connected to the named insured’s work, premises, or products during the policy period.
- The claim and defense. The additional insured tenders the claim to the named insured’s insurance carrier, which evaluates the endorsement wording to determine whether coverage applies, reviews loss history, and determines to what extent claims paid will be covered.
Real Claim Examples Involving Additional Insured Endorsement
Scaffolding Collapse on a Renovation Project
A general contractor required its scaffolding subcontractor to name it as an additional insured using CG 20 10 (cg2010) for ongoing operations on construction projects. During the renovation, a section of scaffolding collapsed, causing bodily injury to two workers from another trade. Because the GC held valid additional insured status tied specifically to the scaffolding sub’s ongoing work, the sub’s insurance carrier defended and indemnified the GC, keeping the claim off the GC’s own general liability policy and avoiding increased premium rates.
Completed Operations Gap After Project Finish
A project owner was named additional insured on a plumbing contractor’s policy, but the endorsement used was CG 20 10 (cg2010) without the completed operations extension (cg2037). Eighteen months after the building was occupied, a pipe fitting failed due to faulty work and caused property damage, triggering a lawsuit against both the plumber and the developer. Because the endorsement forms did not extend to completed operations, the developer had no primary coverage under the plumber’s policy and had to rely on its own insurance and legal defense, creating coverage gaps that could have been avoided.
Landlord Named Additional Insured on a Tenant’s Policy
A commercial landlord required a retail tenant to add it as an additional insured under a blanket endorsement, CG 20 26 (automatic additional insured provision), per the lease agreement. A customer slipped on a wet floor inside the tenant’s space and suffered bodily injury, suing both the tenant and the landlord. The blanket endorsement’s automatic status meant the landlord did not need to be separately scheduled, and the tenant’s insurance carrier picked up the landlord’s defense without a coverage dispute, demonstrating the value of proper additional insured language in business contracts.
Additional Insured Endorsement vs. Certificate of Insurance: What Is the Difference?
Additional insured endorsement and certificate of insurance are related but distinct documents that insurance companies and agencies frequently confuse in practice. The endorsement is the contractual mechanism that actually creates coverage, while the certificate is only a summary snapshot of the policy at a point in time and does not modify coverage limits or insurance requirements.
| Comparison area | Additional Insured Endorsement | Certificate of Insurance |
|---|---|---|
| Primary use case | Legally extends policy coverage to a third party per insurance requirements | Provides evidence that a policy exists during the policy period |
| Coverage / concept type | Contractual risk transfer mechanism with primary coverage | Informational document, non-binding |
| Typical exclusions | Limited to scope of coverage named in the specific form (ongoing vs. completed operations) | Does not itself grant, alter, or restrict coverage or coverage limits |
| Who is most affected by errors | Additional insured party left without defense in a real claim involving injury or damage | Certificate holder relying on inaccurate or outdated information about vendor insurance |
| Common mistakes | Wrong endorsement forms issued for the contract’s actual scope, creating coverage gaps | Treated as proof of coverage instead of a mere summary by insurance companies |
What Are the Most Common Mistakes With Additional Insured Endorsement?
- Treating a certificate of insurance as a guarantee of additional insured coverage, when the certificate has no legal effect on the policy itself or the insurance protection provided.
- Issuing a CG 20 10 (cg2010) without confirming whether the construction agreement requires completed operations coverage (cg2037), leaving the additional insured exposed after project completion and creating significant coverage gaps.
- Failing to verify that the endorsement’s effective date aligns with the start of the underlying work and the policy period, creating a coverage gap for early-stage incidents involving bodily injury or property damage.
- Assuming blanket additional insured wording (cg2033 or automatic additional insured provisions) automatically satisfies every contract, when some business contracts require a specifically scheduled endorsement naming the party by title, such as a governmental agency or project owner.
- Overlooking primary and non-contributory language required by the contract, which can shift defense costs back onto the additional insured’s own policy if missing, affecting how insurance companies handle claims paid.
- Not confirming that the named insured’s coverage limits are adequate to cover both the first named insured and the additional insured under a shared aggregate, potentially increasing insurance costs and premium rates for the renewal policy.
- Failing to implement proper compliance monitoring to track when endorsement forms expire or when contractor relationships change, leaving upstream parties without insurance protection.
- Confusing additional insured status with additional interest or loss payee designations, which provide different types of protection under the general liability policy.
How to Explain Additional Insured Endorsement to a Client
Explaining Additional Insured Endorsement to a Personal Lines Client
Additional insured status usually comes up when you’re renting out a property or hiring a contractor for home work. It means another party, like a lender, property manager, or governmental agency, gets added to your policy so they’re protected if something goes wrong connected to your property, such as bodily injury or property damage. It’s a common lease or loan requirement in business contracts, not something to worry about, but we want to make sure the endorsement forms match exactly what’s being asked for to avoid coverage gaps.
Explaining Additional Insured Endorsement to a Small Business Owner
When a client asks you to add them as an additional insured, they want your general liability policy to step in and defend them if a lawsuit comes from your work on their construction projects. We choose the specific ISO endorsements (like cg2010 for ongoing work or cg2037 for completed work) based on your construction agreement, so it covers exactly what they’re requiring with proper primary and non-contributory wording, no more and no less. Getting this right protects your contractor relationships with that client and keeps a claim from spilling over onto their own insurance, while managing your insurance costs and premium rates effectively.
Explaining Additional Insured Endorsement to a CFO or Risk Manager
Your subcontractor agreements require additional insured status, and the endorsement forms we use (such as cg2010, cg2037, cg2033, or cg2038) determine whether that insurance protection covers ongoing operations only or extends through completed operations as well. We recommend confirming primary and non-contributory coverage language and reviewing aggregate coverage limits erosion exposure, since a shared policy limit between the first named insured and multiple additional insureds can leave less coverage available when you actually need it. We can run a compliance monitoring audit against your current subcontractor certificates to identify any coverage gaps, verify proper additional insured language, review your loss history, and ensure all upstream parties have adequate insurance protection. This includes checking that proprietary endorsements from various insurance companies meet your insurance requirements, that self-insured retention levels are appropriate, and that all permit or authorization requirements are documented. We’ll also verify that indemnification provisions in your business contracts align with the scope of coverage provided by the endorsement forms, protecting you from liability risks related to faulty work or injury or damage claims on your construction projects.
Frequently Asked Questions About Additional Insured Endorsement
Does a certificate of insurance prove additional insured status?
No, a certificate of insurance only summarizes what a policy shows at the time it was issued and carries no contractual weight. Only the actual endorsement attached to the policy, such as CG 20 10 (cg2010), CG 20 37 (cg2037), or other ISO endorsements, creates real additional insured coverage. Insurance companies and agencies should never rely on a certificate alone to confirm status for a construction agreement or other business contracts.
What is the difference between CG 20 10 and CG 20 37?
CG 20 10 (cg2010) covers liability arising from the named insured’s ongoing operations, while CG 20 37 (cg2037) extends that insurance protection to completed operations after the work is finished. Many construction agreements require both endorsement forms together, since a defect discovered after project completion involving faulty work would not be covered under cg2010 alone. Confirming which forms apply is one of the most frequent coverage gaps agencies find during contract review and compliance monitoring.
Can additional insured status be added without a written contract?
Coverage can technically be endorsed onto a general liability policy without a written contract, but most insurance carriers and courts look to the underlying agreement to determine the scope of coverage intended. Without a construction agreement or other business contracts specifying the required endorsement type, disputes over what is actually covered become far more likely. Agencies should always request the contract language and insurance requirements before selecting endorsement forms to avoid coverage gaps.
Does additional insured status cover the additional insured’s own negligence?
Generally, additional insured coverage applies to liability arising out of the named insured’s work, not the additional insured’s own independent negligence. Some broader forms and proprietary endorsements extend further, but insurance companies should read the specific additional insured language rather than assume broad protection. This distinction often becomes the central issue in coverage litigation after a claim involving bodily injury or property damage, affecting how claims paid are allocated.
Is blanket additional insured endorsement the same as scheduled additional insured endorsement?
Blanket endorsements, such as CG 20 33 (cg2033) or CG 20 26 (automatic additional insured provisions), automatically extend coverage to any party the named insured is contractually required to add, without listing each party by name. Scheduled endorsements name each additional insured specifically on the policy declarations, such as a project owner, governmental agency, or specific subcontractors. Blanket forms reduce administrative work and insurance costs but still require a qualifying written contract to trigger coverage and maintain proper contractor relationships.
Can an additional insured endorsement be canceled without notice to the additional insured?
In most cases, the additional insured has no independent right to notice of cancellation unless the endorsement or a separate notice of cancellation endorsement specifically provides for it during the policy period. This gap is a frequent source of disputes when an additional insured assumes they will be notified automatically about changes to coverage limits or the renewal policy. Agencies should confirm whether a notice endorsement is included when business contracts require ongoing verification of coverage, and implement compliance monitoring systems to track when insurance requirements change or when contractor relationships end.
What is the difference between additional insured and additional named insured?
An additional named insured has broader rights under the policy, including the ability to make changes, cancel coverage, and receive direct notice from insurance companies. An additional insured only receives coverage for liability arising from the first named insured’s operations as specified in the endorsement forms. The distinction affects premium rates, coverage limits, and who controls the policy during the policy period.
How do primary and non-contributory endorsements work with additional insured status?
Primary and non-contributory wording ensures that the named insured’s general liability policy responds first to a claim, before the additional insured’s own insurance contributes. This non-contributory coverage provision is critical in construction projects where multiple parties have overlapping insurance protection. Without this language, insurance carriers may dispute which policy provides primary coverage, delaying claims paid and increasing liability risks for all parties involved.
What is the role of self-insured retention in additional insured coverage?
Self-insured retention (SIR) is an amount the named insured must pay before the insurance carrier’s obligation begins. When an additional insured makes a claim, the SIR typically must be satisfied by the first named insured before the additional insured receives insurance protection. This can create coverage gaps if the named insured cannot or will not pay the SIR, which is why many construction agreements specify maximum SIR amounts in their insurance requirements.
Related Insurance Terms
- Certificate of Insurance: a document summarizing policy details for a third party, often issued alongside an additional insured endorsement but carrying no legal power to create or modify coverage limits or insurance requirements.
- Indemnification Clause (Indemnification Provisions): contract language requiring one party to cover another’s losses, frequently the trigger that requires additional insured status to be added to a general liability policy to manage liability risks.
- Waiver of Subrogation: a provision preventing an insurance carrier from pursuing recovery against a specific party, often required alongside additional insured status in construction agreements to protect contractor relationships.
- Hold Harmless Agreement: a contractual promise not to hold another party liable for certain losses involving bodily injury or property damage, commonly paired with additional insured requirements to strengthen risk transfer in business contracts.
- Named Insured (First Named Insured): the primary policyholder whose coverage is extended to an additional insured through an endorsement, who controls the policy declarations and renewal policy decisions.
- Primary and Noncontributory Endorsement: a form ensuring the named insured’s policy responds first with primary coverage, before an additional insured’s own coverage contributes to a loss, affecting how insurance companies allocate claims paid.
- Loss Payee: a party designated to receive payment for property damage claims, different from an additional insured who receives liability protection; often confused in vendor insurance arrangements.
- Additional Interest: a party with an insurable interest in the policy who receives notice of cancellation but does not receive liability coverage, unlike an additional insured who gets insurance protection.
- ISO Endorsements (Endorsement Forms): standardized forms developed by Insurance Services Office, including cg2010, cg2037, cg2033, cg2038, cg 20 11, and cg 20 12, that define the scope of coverage for additional insureds.
- Automatic Additional Insured: blanket endorsement language that automatically extends coverage to parties required by written contract, without naming them specifically in the policy declarations.
- Proprietary Endorsements: custom forms developed by individual insurance companies as alternatives to standard ISO endorsements, which may provide different scope of coverage or coverage limits.
- Upstream Parties: entities higher in the contractual chain, such as general contractors, project owners, or governmental agencies, who typically require additional insured status from subcontractors.
- Permit or Authorization: written permission required in some endorsement forms as a condition for coverage to apply, particularly in premises-related additional insured situations.
- Contributing Primary Insurance: coverage that shares loss payment with other policies on an equal basis, as opposed to primary and non-contributory coverage that responds first.
- Compliance Monitoring: systematic tracking of insurance requirements in business contracts to ensure subcontractors and vendors maintain required coverage limits and endorsement forms throughout the policy period.
- Vendor Insurance: coverage provided to or required from vendors, suppliers, and subcontractors, often including additional insured status for the purchasing party.
- Coverage Gaps: periods or situations where expected insurance protection does not apply, often resulting from mismatched endorsement forms or expired policy periods.
- Faulty Work: defective workmanship or materials that may trigger coverage under completed operations additional insured endorsements like cg2037.
Sources and References
- Insurance Services Office (ISO) sample form reference. Additional Insured. IRMI.
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.