The basics
An 'additional insured' endorsement extends your CGL policy's protection to another party — typically a landlord, general contractor, client, or vendor — for liability arising from your work or operations. It is one of the most contractually negotiated parts of commercial insurance.
Why it matters in 2026
Two flavors matter: ongoing operations (CG 20 10 or equivalent) covers the additional insured for liability during the work; completed operations (CG 20 37) extends coverage for claims arising after the project is finished. Construction contracts almost always require both.
How it actually works
The 'blanket additional insured' endorsement automatically grants AI status to any party you have a written contract requiring it. This is cheaper, faster, and reduces certificate management overhead vs scheduled AI endorsements that list each party individually.
Common pitfalls
Watch for 'primary and non-contributory' wording — without it, your policy may share liability with the additional insured's own policy instead of paying first. Many indemnity clauses in commercial contracts require primary and non-contributory coverage; meeting it usually costs nothing extra on a modern CGL.
Practical recommendations
Issuing a fake or unauthorized AI certificate of insurance (COI) is insurance fraud. Always have your broker issue the COI directly to the requesting party from the carrier's system, and never alter a COI.
Key takeaways
- Understand the structure before you shop.
- Compare quotes from at least three carriers.
- Document everything and revisit coverage annually.
- Pair with related coverage for full protection.
Related reading on InsureLab
Sources & further reading
Frequently asked questions
What is an additional insured endorsement?+
An endorsement extending your CGL coverage to another party (landlord, GC, client) for liability arising from your work or operations.
What is the difference between ongoing and completed operations AI?+
Ongoing operations covers liability during the work; completed operations extends coverage for claims arising after the project is finished.
What does 'primary and non-contributory' mean?+
Your policy pays first and doesn't share liability with the additional insured's own coverage — often required by commercial indemnity clauses.
Are blanket AI endorsements better than scheduled ones?+
Usually yes — they automatically grant AI status to any party you have a written contract requiring it, reducing certificate management overhead.
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