CG 20 10 vs CG 20 37: The Two Additional Insured Endorsements Explained
CG 20 10 covers you while the work is happening; CG 20 37 covers you after it's done. Why you need both, the edition-date wrinkle, and how the gap actually shows up in claims.
Travis
Diamond Flooring Starts Next Week
2 coverage gaps—we've reached out and resolved this before work begins.
- Emailed Vendor
- Verified with Insurance Broker
- Updated new COI in system
Diamond Flooring starts next week. Travis finds that the general liability limit needs an increase and the additional insured is not listed, emails the vendor, verifies coverage with the insurance broker, and updates the new COI in the system before work begins.
CG 20 10 and CG 20 37 are the two standard ISO endorsements that grant additional insured status on a commercial general liability policy — and the difference between them is when the protection applies. CG 20 10 covers ongoing operations: claims arising while the work is being performed. CG 20 37 covers completed operations: claims arising after the work is done. Require only the first — which is exactly what most requirement schedules do — and your protection ends at substantial completion, which in construction is precisely when a large share of the claims begin.
CG 20 10: while the work is happening
The workhorse endorsement. Grants your entity additional insured status for liability "caused, in whole or in part," by the named insured's acts or omissions in the performance of ongoing operations for you. The sub's ladder falls on a visitor mid-job; the landscaper's mower throws a rock through a windshield — ongoing operations, CG 20 10 territory.
One wrinkle worth knowing: edition dates matter. The 11/85 edition of CG 20 10 was broad enough to cover completed operations too, and older contract templates still ask for it by that edition — but carriers almost never issue it anymore. Post-1993 editions explicitly exclude completed operations. If your requirements language was inherited from a 20-year-old template that says "CG 20 10 (11/85)," what you'll actually receive is a modern edition, and the completed-operations gap will be silently real.
CG 20 37: after the work is done
Grants additional insured status for liability arising out of the named insured's completed work — the "products-completed operations hazard." This is where construction-defect reality lives: the roof that leaks two winters later, the pipe fitting that fails after closeout, the balcony railing that gives way in year three. The work is long done, CG 20 10 has nothing to say, and CG 20 37 is the only reason those claims land on the sub's policy instead of yours.
It is also, consistently, the endorsement most likely to be missing from real certificate stacks. Agents attach the ongoing-operations form and stop; requirement schedules ask for "additional insured status" generically and no one specifies; and nothing about the gap is visible until years later. That's the pattern: CG 20 10 gaps surface during the project, when everyone's watching. CG 20 37 gaps surface years after anyone stopped looking.
The pairing, in practice
| CG 20 10 | CG 20 37 | |
|---|---|---|
| Covers | Ongoing operations | Completed operations |
| Claim examples | Jobsite injury mid-project, damage during the work | Defect, failure, injury after the work is done |
| When gaps surface | During the project | Years later — hardest to fix, easiest to miss |
| Who should require it | Everyone hiring contractors | Everyone whose risk outlives the work — GCs, owners, PMs hiring trades |
Requirements language that closes the gap names both: additional insured status for ongoing operations (CG 20 10 or equivalent) and completed operations (CG 20 37 or equivalent) — "or equivalent" because carriers issue proprietary forms and blanket endorsements that can match the coverage. Equivalents are fine; the verification question is always the same two-parter: does the attached form actually cover ongoing and completed operations, and does the entity on it match your contract exactly? (And per the certificate-reading guide: the answer lives in the attached endorsements, never in the description box.)
One more pairing note: completed-operations protection only helps for as long as the coverage exists — which is why subcontracts require coverage be maintained for 2–10 years post-completion, and why verification doesn't end at closeout.
FAQ
Do I need both CG 20 10 and CG 20 37? If the work being done for you could generate claims after it's finished — construction and trades, essentially always — yes, both. Ongoing-only protection expires exactly when defect claims begin.
What about CG 20 26? CG 20 26 is a broader "designated person or organization" additional insured form not tied to a construction contract relationship — sometimes used for landlords, sponsors, and non-construction relationships. It covers ongoing operations; the completed-operations question still leads back to CG 20 37.
Are blanket additional insured endorsements as good as scheduled ones? They can be — but most trigger only where "required by written contract," so the requirement must actually be written into your contract, and you should confirm the blanket form includes completed operations (many don't).
How long after project completion does CG 20 37 protect me? As long as the policy carrying it stays in force. The endorsement doesn't create a tail — your contract's "maintain coverage for X years after completion" clause does, and only if someone verifies it's being honored.
The CG 20 37 gap is the single most common finding when Travis reads a stack of "compliant" certificates. Run yours through Tightrope's free plan and see if it's hiding in your files too.