What is a blanket additional insured endorsement?

A blanket additional insured endorsement automatically extends additional insured status to any party you are contractually required to name, without issuing a separate endorsement for each project or MSA. For tower contractors working under multiple turf vendors simultaneously, blanket AI is essential because it ensures every MSA requirement is automatically satisfied when the contract is signed. The alternative, scheduled additional insured, requires issuing a new endorsement for each party, creating administrative gaps between contract execution and endorsement issuance. Most specialty tower programs include blanket AI with primary and noncontributory wording as a standard feature. The blanket endorsement typically references ongoing operations and completed operations, covering the additional insured both during and after your work. Some endorsements use ISO form CG 20 10 (ongoing) paired with CG 20 37 (completed operations), while others use a single blanket form. Confirm your endorsement covers both, as some MSAs specifically call out completed operations additional insured coverage. The trigger for blanket AI is a written contract requiring additional insured status, so always ensure your MSA or subcontract is fully executed before relying on the blanket provision.