Glossary

Endorsement

A written amendment to an insurance policy that adds, removes or changes coverage, limits or conditions, and controls over the base form where they conflict.

Also called: rider, policy endorsement, policy amendment, form endorsement

An endorsement changes a policy after the base form is written. It can add coverage, such as an additional insured endorsement, remove it, as an exclusion does, or modify a limit, condition or definition. Where an endorsement conflicts with the base form, the endorsement controls, which is why a short form at the back of the stack can undo a promise made at the front.

Endorsements are identified by form number and edition date and listed in the forms schedule on the declarations page. ISO numbers follow a pattern: CG 20 10 and CG 20 37 are the two additional insured endorsements most contracts name, for ongoing and completed operations. A manuscript endorsement is drafted for one insured and carries no ISO number.

The usual mistakes are about proof. A certificate of insurance that mentions an endorsement does not attach it, so ask for the endorsement itself. Compare the schedule on the declarations with the forms actually in the policy. And read every new endorsement at renewal, because exclusions and sublimits are often added that way.

the endorsements small businesses most often need lists the ones small businesses most often need, additional insured endorsements explained covers the one contracts demand, and declarations page shows where they are scheduled.

Last reviewed October 10, 2026

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Related terms

Declarations page The front section of a policy that names the insured, policy period, covered locations or operations, limits, deductibles, premium and the forms attached. Exclusion A policy provision that removes coverage for specified perils, property, people or types of loss that the insuring agreement would otherwise include. Additional insured A person or business added by endorsement to someone else's liability policy so it can claim directly for suits tied to the policyholder's work or premises. Manuscript policy An insurance policy whose wording is drafted or heavily negotiated for one insured rather than taken from a standard ISO or insurer form. Certificate of insurance A one-page summary issued by an agent or insurer showing what coverage a business carried on the date issued, which confers no rights on the holder.

Related guides

Additional insured endorsements explained What CG 20 10, CG 20 37, CG 20 26 and CG 20 38 do, how the 04 13 wording limits additional insured coverage, and why a certificate is not the endorsement. AI liability insurance: how insurers are treating artificial intelligence risk Insurers are adding generative AI exclusions to CGL, D&O and E&O forms while a few markets sell affirmative AI cover. What to check in your policies in 2026. AI regulation in insurance: the NAIC bulletin and state rules What the NAIC's 2023 AI model bulletin, Colorado SB21-169 and its regulation, and the EU AI Act require of insurers, and what a business buyer should expect. Anti-concurrent causation clauses: when one excluded cause sinks a claim How the lead-in to the ISO special form's big exclusions works, how California and Texas courts treat it, and what to do when wind and water hit one building. Business auto coverage symbols explained: what each number covers Symbols 1 through 9 and 19 on a business auto declarations page decide which vehicles each coverage applies to. Here is what each means and where gaps appear. Policy cancellation and nonrenewal: notice periods and your rights How insurers cancel or nonrenew commercial policies, the ISO 10-day and 30-day notice baseline, and how New York, Florida and Texas rules change it.

Related tools

Certificate of insurance (COI) review checklist Check a received certificate for the named insured, dates, limits, endorsements and insurer ratings. Each answer becomes a pass or a flag. Contract insurance requirements checker Enter what a contract, lease or subcontract requires and what your policies have, and get a gap list with the endorsements usually used to close each gap.

Related en español

Certificados de seguro: qué prueban y qué no Cómo leer un certificado de seguro ACORD 25, lo que no prueba sobre asegurado adicional o cancelación, y cómo las leyes estatales limitan los certificados. Cobertura de autos contratados y no propios (HNOA): qué cubre y quién la necesita La HNOA cubre a su negocio cuando alquila un auto o un empleado usa el suyo en el trabajo. Cómo paga, qué excluye y dónde comprarla. Cobertura de deterioro de perecederos por falla de refrigeración y apagones Las pólizas de propiedad estándar excluyen el deterioro por cambio de temperatura y apagones externos. Cómo el CP 04 40 y la avería de equipo cubren el hueco. Empleados que manejan su propio auto por trabajo: ¿quién responde? Si un empleado choca su auto personal en un mandado de trabajo, él y el empleador pueden responder. Qué seguro paga primero, los huecos y qué política adoptar. Endosos de asegurado adicional, explicados Qué hace cada endoso CG 20 10, CG 20 37, CG 20 26 y CG 20 38, cómo la edición 04 13 limita la cobertura y por qué el certificado no es el endoso. Seguro de auto comercial: qué cubre y qué deja fuera Cómo funciona la póliza de auto comercial: responsabilidad civil, daños físicos, quién es asegurado, qué vehículos cubre, huecos comunes y qué fija la prima.