Blanket Additional Insured

An endorsement that automatically grants additional insured status to any party the named insured is contractually required to add by written contract, without needing a separate endorsement for each entity. The blanket additional insured endorsement replaces the need for individually scheduled endorsements (like ISO CG 20 10 for each client) by covering all parties required by any MSA, subcontract, or written agreement.

For tower subcontractors who may onboard dozens of carrier clients and general contractors annually — each with their own MSA requirements — blanket AI is essential. Without it, every new MSA requires requesting a separate endorsement from the carrier, creating an administrative gap between contract execution and certificate issuance that delays site access.

The blanket endorsement should cover both ongoing operations and completed operations (equivalent to CG 20 10 + CG 20 37 combined). Some blanket endorsements only cover ongoing operations, leaving a completed operations gap. Verify with your broker that your blanket AI endorsement extends to both. Most specialty tower insurance programs include blanket additional insured with primary and noncontributory wording as a standard feature at no additional cost.

The trigger for blanket AI is a written contract requiring additional insured status. Always ensure your MSA or subcontract is fully executed before relying on the blanket provision.