Additional Insured Endorsement Types

Common ISO Endorsement Forms

The Insurance Services Office (ISO) publishes standardized endorsement forms that modify the Commercial General Liability policy to add third parties as Additional Insureds. Each form provides a different scope of coverage, and venue contracts frequently reference specific form numbers. The most commonly encountered forms in event contracts include:

• CG 20 10 — Additional Insured — Owners, Lessees or Contractors — Scheduled Person or Organization. This form extends coverage to the Additional Insured for liability arising out of the named insured's ongoing operations. It is the most commonly required form for event venue rentals because it covers claims arising from the event organizer's activities at the venue.
• CG 20 26 — Additional Insured — Designated Person or Organization. This is a broader form that provides coverage to the Additional Insured without limiting it to "ongoing operations." Some venues prefer this form because it can extend coverage to claims arising after the event concludes, such as delayed-onset bodily injury claims.
• CG 20 37 — Additional Insured — Owners, Lessees or Contractors — Completed Operations. This form extends coverage to the Additional Insured for liability arising from the named insured's completed operations. In the event context, this covers claims that arise after the event ends—for example, a slip-and-fall injury that manifests days later.

Venues requiring both ongoing and completed operations coverage will often mandate CG 20 10 and CG 20 37 together. This combination provides the broadest protection and is increasingly the standard in commercial venue contracts.

Blanket vs. Scheduled Endorsements

Additional Insured endorsements can be issued on a "blanket" or "scheduled" basis. A blanket endorsement automatically extends Additional Insured status to any party required by written contract, without needing to list each party individually. A scheduled endorsement names each Additional Insured specifically on the endorsement.

Most event insurance programs use blanket endorsements for operational efficiency. When an organizer books multiple venues throughout the year, a blanket endorsement eliminates the need to issue a new endorsement for each venue. However, some venues—particularly municipality-owned facilities—require that they be specifically named on a scheduled endorsement, which requires a mid-term policy modification.

Coverage Limitations to Watch

Additional Insured endorsements typically contain important limitations. Coverage extends only to liability caused, in whole or in part, by the acts or omissions of the named insured. This means the venue is covered under the organizer's policy only for claims that connect back to the organizer's event operations. Claims arising solely from the venue's own negligence—such as a pre-existing structural defect—are generally excluded from the Additional Insured endorsement.

Additionally, the 2013 edition of ISO Additional Insured endorsements introduced a limitation capping the Additional Insured's coverage at the lesser of the policy limits or the amount required by the written contract. This "lesser of" provision means that even if an organizer carries $2,000,000 in coverage but the contract only requires $1,000,000, the venue's Additional Insured coverage is capped at $1,000,000. Organizers should align their policy limits with contractual requirements to avoid this issue.