Blanket Additional Insured Endorsements: A Comprehensive Analysis for Brokers

A blanket additional insured endorsement extends coverage under a general liability policy to any person or organization with whom the named insured has entered a written contract requiring that they be added as an additional insured. Instead of scheduling each additional insured individually, the blanket endorsement operates automatically for every qualifying relationship. For a general contractor with 400 active subcontractor and project-owner relationships, the blanket form eliminates the administrative overhead of 400 individual endorsement requests. For the broker, it reduces the number of certificate mismatches, endorsement requests, and policy-change transactions. For the underwriter, it consolidates pricing into one line item.

The risk is that brokers, insureds, and certificate holders treat all blanket forms as equivalent. They are not. The ISO CG 20 33, CG 20 37, and CG 20 38 forms have different trigger language and different coverage scopes. Carrier-specific proprietary forms (Travelers IM 7000, Chubb EXCESS BLANK AI 04 19, Hartford CIG 50 44) have their own idiosyncrasies. This analysis walks through the differences that actually change claim outcomes.

Key Takeaways

• The three main ISO blanket forms (CG 20 33, CG 20 37, CG 20 38) cover different scopes. CG 20 33 covers ongoing operations only. CG 20 37 covers completed operations. CG 20 38 bundles ongoing operations with an automatic trigger for any written-contract party.
• CG 20 33 10 01 uses the language "any person or organization with whom you have agreed in a written contract," which is broader than the 2004 and 2013 editions.
• Travelers, Chubb, and Hartford each issue proprietary blanket forms that in some cases extend coverage further than the ISO equivalents, particularly around completed operations and primary and non-contributory treatment.
• Blanket endorsement pricing typically runs 2% to 7% of the general liability premium for ongoing operations, with a 1% to 3% premium add for automatic completed operations coverage.
• A blanket endorsement does not create additional insured status without a written contract. Oral or post-loss agreements do not trigger the endorsement.
• BrokerageAudit's COI Manager automatically maps each certificate representation to the blanket endorsement on the underlying policy and flags mismatches before certificate issuance.

What the Blanket Endorsement Actually Does

An additional insured endorsement amends the general liability policy to extend coverage for liability arising from the named insured's operations or products to a party specified in the endorsement. A scheduled additional insured endorsement lists each covered party by name. A blanket additional insured endorsement uses a contingent trigger: any party meeting the endorsement's stated conditions is automatically covered.

The most common trigger is a written contract requiring additional insured status, signed prior to the loss. The endorsement reads, with language variations by form and edition, something like: "This insurance applies to any person or organization whom you have agreed in a written contract executed prior to a loss to add as an additional insured."

This structure matters because it shifts the certification burden. Instead of the broker confirming the specific endorsement each time, the broker confirms that (a) the blanket form is on the policy, and (b) the contract between the named insured and the certificate holder meets the trigger criteria. Most contract-administration systems log the presence of such contracts, which makes the blanket form operationally superior to scheduled endorsements for mid-size and large commercial accounts.

What the blanket endorsement does not do is cover operations that fall outside the named insured's activities, claims that arise from the additional insured's independent negligence (in most edition years), or relationships that lack the required written contract.

CG 20 33, CG 20 37, and CG 20 38: The Three ISO Forms That Matter

ISO publishes a family of blanket and near-blanket additional insured endorsement forms. Three appear most often in commercial general liability policies.

The three forms have different edition dates. Each edition changed the trigger language in a way that affects coverage outcomes.

CG 20 33 10 01 (October 2001 edition). The broadest and most insured-friendly edition. Uses language "with whom you have agreed in a written contract" without requiring direct performance of operations for that party. A general contractor's written contract with a project owner extends coverage even when the operations are performed for a sub-party downstream.

CG 20 33 07 04 (July 2004 edition). Added a limitation that the additional insured coverage applies only to the extent permitted by law, restricting coverage where state anti-indemnity statutes limit transfer of liability.

CG 20 33 04 13 (April 2013 edition). Added language limiting coverage to acts "caused in whole or in part" by the named insured. This is the narrow edition. It excludes coverage for the additional insured's own independent negligence, which matters in construction cases where the additional insured's own safety failings contributed to the loss.

CG 20 37 10 01 vs CG 20 37 07 04 vs CG 20 37 04 13. The completed operations blanket form follows the same edition progression. The 2013 edition adds the "caused in whole or in part" language to completed operations claims.

CG 20 38 04 13. A variant that pairs ongoing operations blanket coverage with an automatic trigger for primary and non-contributory treatment when the written contract requires it. Particularly useful for construction and service-industry insureds because primary and non-contributory is almost always required in modern contracts.

Many master service agreements and construction contracts specify a required edition. "CG 20 10 10 93 or equivalent" remains common even though ISO withdrew the 1993 edition years ago. Brokers should understand which edition their contract counterparty expects and confirm the endorsement form code on the policy matches.

See our additional insured analysis for the interaction between blanket forms and scheduled forms on the same policy.

CG 20 33 10 01 vs CG 20 38 04 13 vs CG 20 37 07 04

Three specific form-edition combinations surface repeatedly in commercial disputes. The differences deserve detailed comparison.

CG 20 33 10 01: The Broad Ongoing Operations Form. This edition does not include the "caused in whole or in part" limitation. Coverage extends to any party in a written contract, for any claim arising out of the named insured's ongoing operations. Courts have broadly construed this edition to extend defense and indemnity to additional insureds even when the named insured's operations were only one of several causes of the loss. The 2001 edition is the preferred form for insureds that operate in jurisdictions applying concurrent causation analysis.

CG 20 38 04 13: Blanket with Automatic Primary. The 2013 edition paired blanket ongoing operations coverage with primary and non-contributory treatment when the written contract requires it. This is the go-to form for service industry and construction accounts. It reduces the need for a separate CG 20 01 primary and non-contributory endorsement. The cost of the combined form is typically 1% to 2% of GL premium more than CG 20 33 alone.

CG 20 37 07 04: Completed Operations without Narrow Limitation. The 2004 edition of the completed operations form does not include the "caused in whole or in part" limitation added in 2013. For construction work with long tail exposure (products-completed operations claims emerging 5 to 10 years after project completion), this edition extends coverage more broadly than the 2013 edition. General contractors frequently require this specific edition (or its 2001 predecessor) in subcontractor agreements.

The choice among these forms depends on three factors: the nature of the insured's operations, the contract requirements from downstream parties, and the state law governing anti-indemnity and concurrent causation. Brokers writing commercial accounts in construction, energy, and manufacturing should default to the broader 2001 or 2004 editions when the carrier allows the choice. Carriers that have moved to 2013 editions only may require negotiated manuscript language to achieve equivalent coverage.

Carrier-Specific Blanket Forms: Travelers, Chubb, Hartford

Three major carriers issue proprietary blanket additional insured forms that depart from ISO language.

Travelers (IM 7000 family, LRL 07 11). Travelers' primary blanket form covers ongoing operations for parties in written contracts and includes an automatic primary-and-non-contributory treatment when required by contract. The Travelers form uses a slightly different trigger: "any organization that you agree in a written contract to add as an additional insured, subject to the limitations noted in the endorsement." The key limitations restrict coverage for the additional insured's sole negligence and for claims arising out of professional services. Travelers typically pairs the blanket with their CG 20 01-equivalent primary and non-contributory language at no additional premium on accounts over $25,000 in GL premium.

Chubb (EXCESS BLANK AI 04 19, CHUBB AI END 07 14). Chubb's blanket form is generally considered the broadest in the market. It covers ongoing operations, completed operations (for written contracts requiring products-completed operations coverage), and includes primary and non-contributory treatment. Chubb also offers a manuscript blanket form for high-value accounts that extends coverage to waiver of subrogation without a separate CG 24 04 endorsement. The Chubb forms are priced at a premium relative to ISO blanket equivalents but bundle coverage that would require three to four separate ISO endorsements.

Hartford (CIG 50 44, HG 00 01 06 05). Hartford's blanket form for middle-market commercial accounts follows the CG 20 33 structure but adds a 30-day notice of cancellation requirement to additional insureds scheduled through the blanket trigger. This is unusual. Most blanket forms do not include notice requirements. Hartford's addition of notice, while operationally useful for certificate holders, creates a compliance obligation on Hartford that some underwriters will not accept on smaller accounts.

Other carriers (Liberty Mutual, AIG, Zurich, CNA) each have proprietary blanket forms with their own variations. Brokers placing accounts with any of these carriers should request the specific endorsement form in writing and match the form to the certificate representations before issuing.

Ongoing Operations vs Completed Operations Coverage

The distinction between ongoing and completed operations is the most commonly missed coverage issue in blanket additional insured placement.

Ongoing operations. Covers claims arising from the named insured's work while the work is being performed. A slip-and-fall at an active construction site, a vehicle collision while the named insured is performing landscaping services, a spill during the named insured's installation of equipment. The ongoing operations trigger ends when the work is "completed" under the policy definition.

Completed operations. Covers claims arising from the named insured's work after the work is completed. A defective weld that fails 18 months after project completion, a contaminated product that causes injury years after delivery, a roof installation that leaks during a storm two years later. These are products-completed operations claims, typically with much higher severity.

What "completed" means in the policy. The standard CGL form defines "your work" as completed when any of three conditions occur: work called for in the contract is done, work at one site is done even if work remains at other sites, or the product is put to its intended use by any person or organization (whichever is earliest).

Many brokers assume that a CG 20 33 ongoing operations endorsement extends to completed operations claims. It does not. A separate CG 20 37 (or equivalent carrier form) is required. Agencies that issue certificates showing "ongoing and completed operations" additional insured status when only the CG 20 33 is on the policy create direct E&O exposure.

For construction accounts, the standard package should include:

1. CG 20 33 or CG 20 38 (ongoing operations blanket)
2. CG 20 37 (completed operations blanket)
3. CG 20 01 or CG 20 38 (primary and non-contributory)
4. CG 24 04 (waiver of subrogation, often required alongside AI status)

The combined cost runs 6% to 12% of the GL premium for most mid-size construction accounts. The alternative (scheduled endorsements per party) runs $25 to $250 per party and scales linearly with the number of contracts.

Which Carriers Offer Blanket Additional Insured Coverage

Most US commercial GL carriers offer blanket additional insured coverage on accounts above minimum thresholds. Below is the general availability pattern as of 2026.

Smaller carriers and regional mutuals often only offer scheduled additional insured endorsements. Surplus lines markets (Lloyd's syndicates, Markel, Scottsdale) typically offer blanket coverage on accounts over $10,000 in GL premium, though terms vary by broker of record.

Premium Impact: What Brokers Actually Charge

Blanket additional insured endorsements carry real premium. The pricing ranges depend on the carrier, the account size, the operations, and whether the endorsement includes automatic primary and non-contributory treatment.

Ongoing operations blanket alone (CG 20 33 equivalent). Typically 2% to 5% of GL premium. A policy with $15,000 GL premium would see a $300 to $750 blanket endorsement charge.

Ongoing plus completed operations blanket. Typically 3% to 7% of GL premium. The same $15,000 policy would see $450 to $1,050 in endorsement charges.

Ongoing, completed, primary and non-contributory, and waiver of subrogation bundled. Typically 5% to 10% of GL premium. The $15,000 policy would see $750 to $1,500 in additional premium.

Account-specific deviations. Chubb Commercial Insurance, for instance, frequently offers blanket coverage at no additional cost on accounts where the primary GL premium exceeds certain thresholds and the operations are classified in non-construction class codes. Travelers offers similar pricing concessions on middle-market Commercial Package accounts.

Compared to scheduled endorsements (which typically cost $25 to $250 per party and require a new endorsement for each addition), the blanket form is economically superior for insureds with more than 10 to 15 active contract relationships per year. For insureds with fewer than 5 active relationships, scheduled endorsements may actually cost less.

A waiver of subrogation endorsement is often bundled with the blanket additional insured, but the two are distinct coverages and each should be verified separately on the policy.

Common Mistakes in Blanket Endorsement Placement

Four recurring errors dominate E&O claims involving blanket additional insured endorsements.

Confusing ongoing with completed operations. An insured has CG 20 33 (ongoing only) on the policy. The agency issues certificates indicating "additional insured for ongoing and completed operations." A completed operations claim hits. The additional insured tenders. The carrier denies because CG 20 37 is not on the policy. The agency pays.

Contract signed after loss. The blanket trigger requires a written contract signed before the loss. Parties sometimes amend or retroactively ratify contracts after incidents occur. The blanket endorsement does not pick up these retroactively added parties. Agencies should confirm contract execution dates before issuing certificates to new parties.

Wrong edition date. A commercial contract requires CG 20 10 10 93. The carrier issues CG 20 10 04 13. The agency issues the certificate claiming compliance with the contract. The contract counterparty's risk team identifies the edition mismatch. The contract counterparty demands a revised endorsement. The insured faces contract breach exposure until resolved.

State law override. California anti-indemnity laws (Civil Code 2782) limit the scope of additional insured coverage in certain construction contracts. The blanket endorsement may be void or void-in-part as to those claims. Agencies operating in California should understand how Civil Code 2782 interacts with the blanket forms issued on their accounts.

Each of these errors is preventable with policy review at the point of certificate issuance. Manual review scales poorly as certificate volume grows. See the certificate issuance workflow for structured processes.

Using BrokerageAudit for Blanket Endorsement Management

We built the COI Manager to handle exactly this scenario. The system reads each certificate representation, checks the underlying policy for the specific blanket endorsement form and edition, and flags mismatches before the certificate is issued.

For incoming certificates from subcontractors or vendors, the system verifies that the blanket form on the policy actually covers the specific contract relationship, checks edition dates against contract requirements, and identifies the most common state-law overrides that affect coverage.

Agencies with more than 100 active certificates per month typically save 15 to 25 hours per week on blanket endorsement verification alone.

See also our additional insured endorsement guide for more on when scheduled versus blanket forms make sense.

Frequently Asked Questions

What is a blanket additional insured endorsement?

A blanket additional insured endorsement is a general liability policy endorsement that automatically extends coverage to any person or organization with whom the named insured has a written contract requiring additional insured status. Unlike a scheduled additional insured endorsement (which lists each covered party by name), the blanket form uses a contingent trigger. Every qualifying written contract produces automatic coverage without a separate endorsement request. The most common ISO forms are CG 20 33 (ongoing operations), CG 20 37 (completed operations), and CG 20 38 (ongoing with automatic primary and non-contributory).

What is the difference between scheduled and blanket additional insured?

A scheduled additional insured endorsement names each covered party individually. Every new party requires a new endorsement request. A blanket additional insured endorsement covers any party meeting the trigger conditions (typically a written contract signed before the loss) without individual scheduling. Scheduled endorsements typically cost $25 to $250 per party. Blanket endorsements cost 2% to 7% of the GL premium and cover unlimited parties meeting the trigger. Blanket is more economical for insureds with 10 or more active additional insured relationships per year.

Which ISO forms (CG 20 10, CG 20 33, CG 20 37) are blanket forms?

CG 20 10 is a scheduled ongoing operations form, not a blanket form. CG 20 33 is the blanket ongoing operations form. CG 20 37 is the blanket completed operations form. CG 20 38 is a blanket ongoing operations form bundled with automatic primary and non-contributory treatment. CG 20 26 is a broader scheduled or blanket form depending on the edition and carrier manuscript. Each form has multiple edition dates (1993, 2001, 2004, 2013), and the edition affects coverage scope. The 2013 editions added "caused in whole or in part" language that narrows coverage compared to the 2001 and 2004 editions.

Do blanket endorsements cover ongoing or completed operations?

It depends on the specific form. CG 20 33 covers ongoing operations only. CG 20 37 covers completed operations only. CG 20 38 covers ongoing operations with bundled primary and non-contributory treatment but does not automatically include completed operations. For full coverage across both phases, the policy needs both CG 20 33 (or CG 20 38) and CG 20 37, or a carrier-specific bundled form like Chubb's EXCESS BLANK AI 04 19 which covers both. Agencies that issue certificates claiming "ongoing and completed operations" without both forms on the policy create direct E&O exposure.

Which carriers offer blanket additional insured endorsements?

Most major US commercial GL carriers offer blanket additional insured coverage on accounts meeting minimum premium thresholds. Travelers, Chubb, Hartford, Liberty Mutual, AIG, Zurich, and CNA all have proprietary blanket forms in addition to the ISO forms. Minimum thresholds range from $5,000 (Travelers, Liberty Mutual, CNA) to $20,000 (Zurich). Smaller regional mutual carriers often only offer scheduled forms. Surplus lines markets typically offer blanket coverage on accounts over $10,000 in GL premium, with terms varying by broker and carrier.

What is the premium impact of adding a blanket additional insured endorsement?

Ongoing operations blanket coverage typically costs 2% to 5% of the GL premium. Ongoing plus completed operations blanket runs 3% to 7%. A full package including ongoing, completed, primary and non-contributory, and waiver of subrogation can run 5% to 10% of the GL premium. Carrier and account-specific variations apply. Chubb frequently includes blanket coverage at no additional charge on accounts meeting certain premium and classification thresholds. For insureds with 10 or more active additional insured relationships per year, the blanket endorsement is typically more economical than scheduled endorsements.

Written by Javier Sanz, Founder of BrokerageAudit. Last updated April 2026.

Match blanket endorsement coverage to every certificate before issuance. BrokerageAudit's COI Manager checks the blanket form and edition on the policy against each certificate representation, flags scope mismatches between ongoing and completed operations, and logs the audit trail for E&O defense. Explore COI Manager