An article by Noelle McCall, CIC, CRM, CCIP, ACRA, CISR

If you or your clients hire subcontractors to work on construction projects, you've probably heard someone say, “Make sure we’re listed as an additional insured!” But what does that really mean—and how can you tell if the right insurance form is being used?

Most construction contracts require subcontractors to list the general contractor and project owner as additional insureds on their liability insurance. This protects those parties if they’re named in a lawsuit over bodily injury or property damage related to the project.

Insurance companies often use standard forms developed by the Insurance Services Office (ISO) to add additional insured coverage to policies. These forms are widely recognized and used in the industry—but not every form that looks like an ISO form actually is one.

So, how can you tell if you’re looking at a true ISO additional insured form?

Here are four simple things to check, using a commonly required ISO additional insured form as an example: Additional Insured - Owners, Lessees or Contractors - Scheduled Person or Organization ISO form CG 20 10 12 19.

1. Check the Form Number

A real ISO form has 10 characters in its number.
For example: CG 20 10 12 19

“CG” means it’s for Commercial General Liability policies.

“20” indicates it’s an additional insured endorsement.

The last four digits (12 19) are the edition date—December 2019 in this case.

If the form number doesn’t follow this pattern, it might not be an ISO form.

2. Check the Edition Date

ISO has filed different versions of additional insured forms over the years. Legitimate versions of the ISO CG 20 10 form include:

• 11 85 (November 1985)
• 10 93 (October 1993)
• 03 97 (March 1997)
• 10 01 (October 2001)
• 07 04 (July 2004)
• 04 13 (April 2013)
• 12 19 (December 2019—the most current version)

Make sure the version you're being given is one of these.

3. Look for the Copyright Statement

A true ISO form will say one of the following:

• “© ISO Properties, Inc., [year]”
• “© Insurance Services Office, Inc., [year]”

If there is no copyright notice on the form, then:

• it could be an ISO form and the insurer just forgot to add the copyright notice—not likely, but possible
• the insurer might be using an ISO form in violation with copyright law—not likely, but possible
• it could be a carrier-specific form—much more likely

If the form says the following, then it might use some ISO wording, but it’s been altered—and is not a true ISO form:

“Includes copyrighted material of Insurance Services Office, Inc. with its permission”

4. Compare the Wording

The only way to know for sure is to compare the form side-by-side with a genuine ISO form (same number and edition). If anything is different—even just one sentence—it’s not a real ISO form.

Pro Tips:
✔️ For insurance agents/brokers:
Avoid saying a specific ISO form is included on a certificate of insurance. Instead, attach the actual form so others can review it for themselves.

✔️ For contract drafters/project managers:
When requiring additional insured coverage, be specific. Ask for a particular ISO form, or a form that is "at least as broad as" that ISO form. Don't ask for an ISO form "or its equivalent" as this can cause confusion and disagreements—especially at claim time—over what is equivalent.

Understanding the details behind additional insured forms can save time, money, and headaches. Taking a few minutes to check the form number, edition date, copyright, and wording can help you and your clients reduce and transfer contractual risk.