Blanket Additional Insured

A blanket additional insured endorsement automatically extends additional insured status to any party your contract requires — without naming each party individually on the policy. It activates the moment a qualifying written contract is signed, making it the most efficient way for contractors, property managers, and service businesses to satisfy vendor and landlord insurance requirements at scale.

Who this is for: Business owners who sign multiple contracts with different clients, landlords, or project owners and need to add those parties as additional insureds routinely.

TL;DR / Key Takeaways

• A blanket additional insured endorsement covers any third party required by a written contract — no separate endorsement needed per party.
• Coverage only applies when triggered by a qualifying written agreement executed before a loss.
• It does not give additional insureds unlimited rights; they are still subject to your policy's limits and exclusions.
• Blanket endorsements typically add $50–$300 per year to a commercial general liability (CGL) premium, depending on trade and carrier.
• Always verify the endorsement language matches what your contract requires — ISO CG 20 10, CG 20 37, or a manuscript form.

What Is a Blanket Additional Insured Endorsement?

A standard Commercial General Liability (CGL) policy covers your business and its employees. A blanket additional insured endorsement extends that coverage to third parties — such as a general contractor, property owner, or client — whenever a written contract between you and that party requires you to name them as an additional insured.

The word "blanket" is key: instead of submitting a separate endorsement for each new project or client (a scheduled additional insured), the blanket approach applies automatically to all qualifying contracts. You do not need to call your insurer every time you sign a new subcontract.

How it differs from a certificate holder: A certificate holder listed on a Certificate of Insurance (COI) receives proof of insurance but gains no coverage rights. An additional insured — blanket or scheduled — actually shares your liability policy's protection for claims arising out of your operations.

Blanket vs. Scheduled Additional Insured: Key Differences

Which ISO Endorsements Apply?

The Insurance Services Office (ISO) publishes standard endorsement forms that most carriers use as a baseline. The most common blanket endorsements for CGL policies are:

Important: Many upstream contracts (especially in construction) require both CG 20 10 and CG 20 37. Using only one may leave you in breach of contract even if the endorsement is otherwise valid.

How Blanket Additional Insured Coverage Is Triggered: A 5-Step Process

1. Execute a written contract. The agreement must exist before the claim-triggering event occurs. Verbal agreements generally do not activate a blanket endorsement.
2. Confirm the contract contains an insurance requirement clause. Language such as "Subcontractor shall name Owner as Additional Insured on its CGL policy" is the standard trigger.
3. Verify your endorsement form matches the contract requirement. If the contract specifies ISO CG 20 10 and CG 20 37, confirm both are on your policy.
4. A covered claim arises from your operations. The claimant or indemnitee submits the claim to your insurer.
5. Insurer confirms the written contract existed at the time of loss. The carrier then extends defense and indemnity to the additional insured up to your policy limits, subject to all exclusions.

Real-World Example: Electrical Subcontractor in Texas

Scenario (illustrative — not a guarantee):

A commercial electrical subcontractor in Houston, TX works on a $2.4M hotel renovation for a general contractor (GC). The subcontract requires the electrician to carry:

• $1M/$2M CGL (occurrence basis) with a blanket additional insured endorsement (CG 20 10 + CG 20 37)
• $1M employer's liability (part of workers comp)
• $2M umbrella

A hotel guest trips over exposed conduit during the project and files a $750,000 bodily injury claim against the GC. Because the electrician's blanket AI endorsement was in place and the subcontract was signed before the incident, the GC's defense costs and settlement share are tendered to the electrician's CGL policy — up to the $1M per-occurrence limit, with the umbrella available beyond that.

The electrician's annual CGL premium: approximately $4,200. The blanket AI endorsement added roughly $180/year — a fraction of the claims exposure it managed.

State note: Texas is one of very few states where workers compensation is not mandatory for private employers [verify state rules for current requirements], which makes the liability exposure and additional insured chain even more significant on Texas construction projects.

How Much Does a Blanket Additional Insured Endorsement Cost?

Cost varies by trade, revenue, and carrier, but industry-typical ranges:

Costs above are illustrative ranges based on industry data; your actual premium depends on payroll, revenue, claims history, and carrier underwriting guidelines. Contact [Morrow to confirm] for a quote specific to your trade.

Common Pitfalls That Void Blanket Additional Insured Protection

• No written contract: If the agreement was verbal or unsigned at the time of loss, most endorsements will not activate.
• Wrong form number: A contract requiring CG 20 10 is not satisfied by a general "blanket AI" notation if the carrier's form is materially narrower.
• Completed operations gap: Using only CG 20 10 leaves no coverage for post-construction claims. Many GC contracts mandate CG 20 37 as well.
• Expired policy: A lapsed policy provides no protection even if the underlying contract is still active.
• Carrier-specific manuscript forms: Some large carriers use proprietary forms that may be broader or narrower than ISO. Read the actual endorsement, not just the form number.

FAQ

What is blanket additional insured?

A blanket additional insured endorsement is a policy modification that automatically grants additional insured status to any third party required by a qualifying written contract — without the policyholder needing to name each party individually or file a separate endorsement for each relationship.

Does a blanket additional insured endorsement replace the need to issue certificates of insurance?

No. A Certificate of Insurance (COI) is still required as proof of coverage. The blanket endorsement determines coverage rights; the COI is the documentation. Most upstream parties will require both.

Can a blanket additional insured endorsement be on a claims-made policy?

Yes, but timing is critical. On a claims-made policy, both the written contract must have been in effect and the claim must be reported during the policy period (or extended reporting period). This makes blanket AI endorsements on claims-made forms more complex to manage than on occurrence-based CGL policies.

Does being a blanket additional insured give the upstream party unlimited coverage?

No. The additional insured is subject to the same per-occurrence and aggregate limits as the named insured, the same policy exclusions, and the same deductible or self-insured retention (SIR). Being an additional insured is not the same as having a separate, independent policy.

What is the difference between blanket additional insured and waiver of subrogation?

These are two separate provisions. A blanket additional insured endorsement allows a third party to make claims under your policy. A blanket waiver of subrogation prevents your insurer from suing that third party to recover losses paid under your policy. Many contracts require both. They serve different functions and must each be confirmed on your endorsement.

Do I need primary and non-contributory language as well?

Likely yes, if your contracts are in construction or real estate. "Primary and non-contributory" language means your policy pays first before the additional insured's own coverage kicks in. Without it, insurers may attempt to share the loss proportionally. Most modern GC subcontracts require primary/non-contributory to be stated explicitly in the endorsement.

Will the blanket endorsement automatically cover new projects?

Yes — that is the primary benefit. As long as a new project is covered by a written contract that meets the endorsement trigger, it is automatically included without any action required on your part during the policy period.

Can property managers use blanket additional insured endorsements?

Yes. Property managers frequently add building owners as additional insureds on their general liability policies. A blanket endorsement is ideal when managing a portfolio of properties under separate management agreements, eliminating the need for individual endorsements per building.

Why Morrow for Blanket Additional Insured Endorsements

1. Independent agency access: Morrow places coverage with multiple admitted carriers, allowing us to compare endorsement language — not just price — across ISO and manuscript forms to find the one that actually satisfies your contract.
2. Contract-language review: Our producers review your underlying subcontracts and vendor agreements to confirm the endorsement form, trigger language, and primary/non-contributory requirements align before a loss occurs.
3. Fast COI turnaround: We issue Certificates of Insurance with additional insured notation same-day for most requests, so project delays caused by certificate bottlenecks are minimized.
4. Trade specialization: Morrow works extensively with construction subcontractors, property managers, and service contractors — the trades that live and breathe blanket AI requirements daily.
5. Claims advocacy: If a blanket AI claim is disputed — because a carrier questions whether the written contract trigger was met — our team advocates on your behalf through the claims process rather than leaving you to navigate carrier correspondence alone.

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Related Pages

• Commercial General Liability Insurance — Coverage Overview
• Additional Insured vs. Certificate Holder: What's the Difference?
• Waiver of Subrogation Explained
• Commercial Insurance for General Contractors
• How Much Does Commercial General Liability Insurance Cost?

Author: [Morrow to confirm] — Licensed P&C Insurance Broker, [credentials/designations to confirm] Published: June 2026 Last updated: June 2026

Sources: - Insurance Services Office (ISO) — CGL Endorsement Forms CG 20 10, CG 20 37, CG 20 38 - National Association of Insurance Commissioners (NAIC) — Commercial Lines Policy Guidance - Insurance Information Institute (III) — Additional Insured Coverage Resources - Texas Department of Insurance (TDI) — Commercial Insurance Requirements - Construction Financial Management Association (CFMA) — Contract Insurance Requirements Guidance