What Is an Insurance Endorsement? Types, Form Numbers and How to Read One
An insurance endorsement is a form attached to a policy that changes it. Almost everything a GC or property manager asks a sub for beyond the basic limits (being added as an additional insured, a waiver of subrogation, primary and noncontributory wording) exists only as an endorsement. This guide covers how an endorsement differs from the certificate, how to read the form number at the bottom of the page, the endorsements subs are asked for and their standard forms, and how to check one.
An insurance endorsement is a form attached to an insurance policy that changes it: it adds or removes coverage, names another party, or changes a condition. It is part of the policy, unlike the certificate of insurance, which only summarizes the policy and says it doesn't change it. Standard endorsements carry a form number and edition, such as CG 20 10 04 13. The ones GCs and property managers require from subs are additional insured (CG 20 10, CG 20 37, CG 20 26 or blanket forms), primary and noncontributory (CG 20 01) and waiver of subrogation (CG 24 04, CA 04 44, WC 00 03 13).
In this guide
What an endorsement does
A commercial policy is built from a main coverage form plus whatever endorsements are attached to it. The main form is the same for everyone who buys that kind of policy; the endorsements are what make it fit this insured, this state and these contracts. Each one starts with the same line: This endorsement changes the policy. Please read it carefully.
An endorsement can do one of four things:
Add someone
Make another person or organization an insured, as an additional insured endorsement does for a GC or owner.
Change a condition
Rewrite one of the policy's rules: which policy pays first, whether the insurer can recover from you, how much notice it gives.
Add coverage
Extend the policy to something the main form leaves out, or raise a limit for a project.
Take coverage away
Exclude a kind of work or a kind of claim. These are the ones that hurt, and the certificate never shows them.
Some endorsements are attached to every policy written in a state, to bring the form in line with its law. Others are added because the insured asked, usually because a contract required them. Those are the ones this guide is about. In some lines of insurance an endorsement is called a rider; it's the same thing.
Endorsement vs certificate of insurance
The certificate is how most people meet an endorsement, which is why the two get confused. They are different documents from different people:
| Certificate of insurance (ACORD 25) | Endorsement | |
|---|---|---|
| What it is | A one-page summary of the policies | Part of the policy itself |
| Who issues it | The agent or broker | The insurer, as part of the policy |
| What it can do | Describe coverage. It states that it doesn't amend, extend or alter it | Change the coverage |
| Where it shows | The ADDL INSD and SUBR WVD boxes, and wording in Description of Operations | A form with its own number, behind the declarations or sent as separate pages |
| What it proves | That the agent believes the endorsement exists | That it does |
So a ticked ADDL INSD box with no endorsement behind it is a statement, not coverage. That's also why being the certificate holder gives you nothing on the policy: the certificate holder gets the certificate, and only an endorsement puts you on the policy. The COI audit checklist covers the rest of the certificate.
How to read an endorsement and its form number
Standard endorsements are written by ISO, which drafts the commercial forms most insurers use, and by NCCI for workers' comp. Their pages look alike. Read these parts, roughly top to bottom:
- Policy number, at the top. It should match the policy on the certificate.
- Title, in capitals, such as Additional Insured – Owners, Lessees or Contractors – Scheduled Person or Organization.
- What it modifies: "This endorsement modifies insurance provided under the following: Commercial General Liability Coverage Part".
- The schedule: the names, projects, locations or numbers the endorsement applies to. Blank, or "as required by written contract", on a blanket form.
- The body: what it changes.
- The form number and edition, at the bottom of every page.
The form number is what to look for first, because it tells you which standard wording you're reading. Taking CG 20 10 04 13 apart:
CG
The coverage part: commercial general liability
20 10
The form: additional insured for owners, lessees or contractors, scheduled
04 13
The edition: April 2013
The letters you'll meet most often are CG (general liability), CA (commercial auto), CU (commercial umbrella), IL (interline: forms that apply across several coverage parts) and WC (NCCI's workers' comp forms, which print the edition as, for example, Ed. 4-84).
The edition matters. The same form number can cover different things in different editions. CG 20 10 is the example everyone in construction learns: its 11 85 edition reached the sub's completed work, and from the 10 93 edition onward it covers ongoing operations only, which is why GCs now ask for CG 20 37 as well (CG 20 10 vs CG 20 37). Forms that aren't ISO or NCCI carry the insurer's own number. They can be broader or narrower than the standard form, so read them rather than assume.
The endorsements subs are asked for, by form number
A typical insurance exhibit in a subcontract or vendor agreement asks for some or all of these. Each standard form is listed with the guide that covers it:
| Endorsement | What it does for you | Standard forms | Guide |
|---|---|---|---|
| Additional insured, ongoing and completed operations | Puts you on the sub's general liability policy, while the work is under way and after it's finished | CG 20 10, CG 20 37 | CG 20 10 vs CG 20 37 |
| Additional insured, designated person or organization | Names you with no project or location attached, as owners, landlords and property managers often are | CG 20 26 | CG 20 26 |
| Blanket additional insured | Covers anyone the sub's written contract requires, without naming them | CG 20 33, CG 20 38; completed operations CG 20 39, CG 20 40 | Blanket additional insured |
| Additional insured on auto | The auto policy's version, for the sub's vehicles | CA 20 48 | |
| Primary and noncontributory | Makes the sub's policy pay before yours, without asking yours to share | CG 20 01 | Primary and noncontributory |
| Waiver of subrogation | Stops the sub's insurer suing you after it pays a claim | CG 24 04 (GL), CA 04 44 (auto), WC 00 03 13 (workers' comp) | Waiver of subrogation |
| Notice of cancellation | CG 02 24 gives the sub more notice; only an insurer's own third-party form notifies you | CG 02 24, and insurers' own forms | Notice of cancellation |
| Per project aggregate | Gives each project its own general liability aggregate, so one job's claims don't use up another's | CG 25 03 |
Two kinds of endorsement never appear on a request list, and both matter. Exclusions take coverage away, such as limiting the policy to the work classes listed on it, or excluding residential work. State amendatory endorsements rewrite parts of the policy to fit a state's law. Neither shows on the certificate. The full set of requirements, with limits, is in subcontractor insurance requirements.
Blanket vs scheduled
Most of the endorsements above come in two shapes, and they're checked differently:
- Scheduled: the endorsement names you, and sometimes the project, in its schedule. Check the name is your exact legal entity, and that the owner is there too if your prime contract requires it.
- Blanket: the endorsement applies to anyone the sub agreed in a written contract to cover, and names no one. Nothing on the page proves it applies to you; your signed subcontract does. So the subcontract has to be signed, and has to require the endorsement, before the work starts.
Subs who work for many GCs usually carry blanket forms, because scheduling every customer is impractical. Blanket forms aren't all alike either: CG 20 33 and CG 20 38 differ on whether the owner above you is covered.
How to check an endorsement
Ask for the pages, not the boxes
Require the endorsement pages with every certificate. The sub's agent can attach them to the same PDF.
Match the policy
The policy number and dates on the endorsement should match a policy on the certificate. An endorsement from last year's policy covers nothing this year.
Read the form number and edition
Is it the standard form your contract asks for, an older edition, or the insurer's own wording?
Check the schedule
Your exact name on a scheduled form; blanket wording, and a signed contract, on a blanket one.
Look again at renewal
Endorsements can fall off when a policy renews or moves to a new insurer. Ask for the pages with every renewal certificate.
Several endorsements per sub, each tied to a policy with its own renewal date, is the check that slips first. Insurance endorsement verification reads the forms themselves, and COI tracking software keeps each policy on its own dates.
How TrackMyVendor automates this
- The ADDL INSD and SUBR WVD boxes are read on every coverage row of the certificate, with the carrier, policy number, dates and limits.
- Endorsement forms are read, and additional insured, waiver of subrogation, primary and noncontributory and notice of cancellation forms are recognised by their form number. Pro
- A ticked box with no endorsement behind it is flagged, naming the endorsement and the coverage it's missing from. Pro
Exclusions and other endorsements aren't read, and for a scheduled form we show you the names on it rather than decide whether they match your legal entity. Those stay with you.
See how endorsement verification worksCertificates and endorsements, collected together
Subs and vendors upload the certificate and the endorsement pages through one link — no account, no portal. Every policy is read and tracked on its own dates. Your first 25 contractors are free.
Frequently asked questions
What is an insurance endorsement?
Is an endorsement the same as a certificate of insurance?
What do the numbers on an endorsement mean?
What endorsements should a subcontractor have?
What is the difference between a blanket and a scheduled endorsement?
This guide explains how insurance endorsements commonly work. It isn't insurance or legal advice: form editions, insurer wording and state law differ, and the policy and your contract govern. Ask your broker and attorney about your own requirements.
Insurance on a sub’s certificate
What to require from every sub, one term at a time.
Subcontractor insurance requirements: start here → Coverage, minimums and endorsements to require from subs, with every term below in one table