Guides / COI basics

Blanket Additional Insured Endorsements: How to Tell if One Covers You

By SubCover HQ · Updated Nov 3, 2026 · 2 min read

Many subs' agents will tell you, "You're covered under the blanket endorsement." That can be true, and it's how a lot of additional insured coverage works today. But "blanket" doesn't mean "everyone, always." It means the policy covers anyone who meets the conditions written into the endorsement.

Scheduled vs. blanket

• Scheduled endorsements list each additional insured by name. Adding you means a policy change.
• Blanket endorsements, such as ISO forms CG 20 38 or the "automatic status" endorsements many insurers use, extend additional insured status to any person or organization the insured has agreed in a written contract to add, without listing them.

The conditions that usually apply

1. A written contract. Most blanket endorsements require a written agreement, and many require that it be signed or executed before the injury or damage happens. A handshake deal or a purchase order without insurance language may not qualify.
2. The contract must actually require it. If your subcontract doesn't say the sub will name you as additional insured, the blanket endorsement may not reach you.
3. Ongoing vs. completed operations. Some blanket endorsements cover only ongoing operations. Completed operations may need a separate form, such as CG 20 37 or a blanket equivalent.
4. Who's covered. Some forms cover only the party you contracted with directly, not the owner or other parties above you. If your contract requires coverage for the owner too, check the wording.

What the certificate should show

On the ACORD 25, the ADDL INSD box should be marked on each policy line where you need additional insured status, and the description of operations box should reference the blanket endorsement, ideally with its form number. See our description of operations box guide for sample wording.

What to ask for

• A copy of the blanket endorsement itself, not just the certificate.
• Confirmation that it covers both ongoing and completed operations if your contract requires both.
• Your signed subcontract on file, dated before work starts, with clear additional insured language.

Our guide to CG 20 10 and CG 20 37 covers the scheduled forms these blanket versions are based on.

Key takeaways

A blanket endorsement can save everyone paperwork, but it only works if your signed contract triggers it. Keep the contract, the certificate, and the endorsement together. SubCover HQ checks the ADDL INSD boxes and endorsement references on every certificate for $99/month.

Frequently asked questions

What is a blanket additional insured endorsement?

An endorsement that makes any party the insured agreed in a written contract to add an additional insured, without listing each one by name.

Do I need a signed contract for a blanket endorsement to cover me?

Usually yes. Most blanket endorsements require a written contract requiring additional insured status, often signed before the loss.

Does a blanket endorsement cover completed operations?

Not always. Some cover only ongoing operations. Check the form or ask for a completed operations endorsement too.

How do I verify a blanket endorsement?

Ask the agent for a copy of the endorsement and keep it with the certificate and your signed contract.

This guide is general information, not insurance or legal advice. Endorsement wording varies by insurer; your insurance professional and attorney determine what you should require.