Most general liability policies are occurrence forms. If someone slips in your shop this year and sues three years from now, the policy that was in force the day they fell is the one that answers. Most professional liability, D&O and employment practices policies are claims-made, many malpractice policies are, and cyber forms are written that way too. There, the policy in force the day the claim arrives is the one that answers, and, when there is a retroactive date, only if the mistake happened on or after it. Keeping a claims-made policy alive, renewal after renewal, with the same retroactive date is the whole game. Let it lapse without buying an extended reporting period and every claim that has not shown up yet has no policy to answer it.
What triggers each policy
ISO publishes an occurrence general liability form, CG 00 01, and a claims-made counterpart, CG 00 02. The difference is the trigger: which policy year has to respond.
An occurrence policy covers claims arising out of injury or damage that took place during the policy period, regardless of when the claim is made. A customer hurt in your shop in March who sues two years later lands on the March policy.
A claims-made policy is triggered when a claim is first made against you during the policy period. If the policy carries a retroactive date, the injury, damage or wrongful act behind the claim also has to have happened on or after that date.
Many are also claims-made-and-reported: the claim must be made against you during the policy period and reported to the insurer within the time the policy specifies. A claim made in year one generally has to be reported in year one, or within a short window after it, through the method on the declarations, or coverage can be forfeited.
Retroactive dates and prior acts
The retroactive date is usually listed in the declarations and eliminates coverage for injury, damage or wrongful acts that took place before it, even if the claim arrives during the policy period. Insurers use it to keep known problems out and to cut off stale claims.
On a first claims-made policy it is usually the day that policy starts, and each renewal should carry the same date forward. A new carrier can set its retroactive date back to your original one, which the trade calls prior acts or nose coverage: coverage back to the original effective date of your first policy.
Whether an insurer can move the date forward varies by state; North Carolina's guidelines bar advancing an existing retroactive date without the insured's written consent. Under the ISO claims-made CGL form, an insurer advancing the date opens a gap that triggers the basic extended reporting period. Check the date on every renewal.
Extended reporting periods, the tail
An extended reporting period, or tail, is a window after a claims-made policy ends during which a claim can still be made and treated as if it arrived during the policy period. It only reaches acts, injury or damage that happened after the retroactive date and before the policy ended.
- ISO claims-made CGL (CG 00 02). A basic extended reporting period applies automatically on cancellation or nonrenewal, when the insurer advances the retroactive date, or when the insurer replaces it with an occurrence form: 60 days after the policy ends for unreported incidents, five years for incidents reported to the insurer within those 60 days, with no increase in limits. A supplemental period of unlimited duration is available if requested in writing within 60 days after the policy ends, and it reinstates the aggregate limit.
- Professional liability, D&O and similar policies have their own tail provisions. Any automatic window is short, often 30 to 60 days, and usually applies only when the insurer, not you, cancels or nonrenews, so the tail you buy is what matters.
- State minimums vary. North Carolina's guidelines require a tail offer on cancellation or nonrenewal (except for nonpayment), elected within 30 days: at least one year for non-medical claims, unlimited for medical malpractice, with an aggregate equal to the expiring policy's. They also require an unlimited malpractice tail if the insured dies, becomes permanently disabled, or retires at 65 or older after five or more consecutive years of claims-made coverage.
Why E&O is claims-made and GL usually isn't
Most commercial general liability insurance is written on the occurrence form. Most professional liability, E&O, D&O and employment practices liability is written claims-made. Many malpractice insurers write claims-made, the NAIC notes. Cyber liability forms are written claims-made as well; Connecticut's insurance department approved claims-made cyber forms in 2016 under its claims-made regulations.
The reason is the gap between the mistake and the claim. A slip-and-fall gets reported fast, so the occurrence form works. A bad contract clause, a missed filing, a design error or a data breach can surface years later. The retroactive date and the claims-made trigger let the insurer limit how far back it is on the hook and close a policy year knowing no more claims can come in without a tail. That is why the claims-made form puts continuity on you.
Switching carriers, closing or retiring
Changing carriers on a claims-made line is where people get hurt. The Texas Department of Insurance puts it plainly: prevent gaps by buying run-off (tail) coverage from the old carrier or prior acts (nose) coverage from the new one. I get the new carrier to match the existing retroactive date in writing before the old policy expires, with no day between the two; if it will not, the old carrier's tail is all that protects the years in between.
When you close, retire or move to an occurrence form, ask for the tail before the policy ends; the windows after it ends are short: 60 days to elect the ISO claims-made CGL supplemental period, 30 days after a cancellation or nonrenewal under North Carolina's guidelines. While the policy is in force, report every claim and every circumstance that could become one to the carrier on the risk that day, through the method the policy names.
Professional liability (E&O) and directors and officers policies are where this comes up most; general liability is usually the occurrence form, so if a GL quote comes back claims-made, ask why before you bind.
Common questions
Is claims-made worse than occurrence?
Neither is wrong. Occurrence is simpler: the policy in force when the injury happened responds, however late the claim comes. Claims-made asks you to keep the policy continuous, protect the retroactive date and buy a tail when you stop, and most E&O, D&O and EPLI is written claims-made anyway.
What is a retroactive date?
The earliest date a wrongful act can happen and still be covered under a claims-made policy. It is listed in the declarations on most policies, is usually the start date of your first claims-made policy, and should carry forward unchanged at every renewal. In North Carolina, for example, an insurer cannot advance it without your written consent.
When do I need tail coverage?
Whenever a claims-made policy ends without a replacement that honors your retroactive date: you close, retire, switch to an occurrence form, or the new carrier will not match the date. Ask before the policy expires; the ISO claims-made CGL form gives 60 days after the policy ends to request the unlimited tail, and North Carolina's guidelines give 30 days after a cancellation or nonrenewal.
Do I need a tail when I switch carriers?
Not if the new carrier sets its retroactive date back to your original one, which is prior acts or nose coverage. If it will not, or the dates leave a gap, you need a tail from the old carrier for the years the new policy does not reach.
What does claims-made-and-reported mean?
The claim must be made against you during the policy period and reported to the insurer within the time the policy specifies, usually that same period or a short window after it. A claim made in year one and not reported until year two can be denied even by the same insurer, and the whole claim can be forfeited, so report through the method listed on the declarations as soon as a demand arrives.
Sources
- IRMI glossary: claims-made policy (trigger, retroactive-date rule, most professional, E&O, D&O and EPLI written claims-made)
- IRMI glossary: retroactive date (found in many but not all claims-made policies; keeps known situations and stale claims out)
- IRMI glossary: basic extended reporting period (professional liability automatic windows of 30 to 60 days when the insurer cancels or nonrenews)
- IRMI expert commentary: The Claims-Made CGL Policy (retroactive date in the declarations, basic and supplemental extended reporting periods, gap when the date is advanced)
- IRMI expert commentary: The 2001 ISO CGL Revision (occurrence form CG 00 01 and claims-made form CG 00 02)
- IRMI expert commentary: Claims-Made Policies, Timing Is Everything (most CGL is occurrence; claims-made-and-reported; year-one claim reported in year two denied even by the same insurer)
- Texas Department of Insurance: medical liability insurance guide (occurrence vs. claims-made, tail and prior acts coverage, retroactive date back to the first policy)
- North Carolina Department of Insurance: Guidelines for Claims-Made Policies (tail offer, 30-day election, minimum durations, retroactive-date consent)
- Connecticut Insurance Department: Notice Concerning Claims-Made Cyber Liability Insurance (July 11, 2016)
- NAIC: Medical Malpractice Insurance (many insurers write on a claims-made form basis)
General information about claims-made and occurrence liability forms as of October 2026, not legal or tax advice; your policy language, the ISO form edition in use and your state's claims-made rules control. Coverage depends on underwriting and the terms, conditions and exclusions of the policy actually issued.