8.3 Occurrence vs. Claims-Made Triggers
Key Takeaways
- An occurrence policy is triggered by injury or damage that happens during the policy period, no matter when the claim is reported — standard for the ISO CGL Coverage Form CG 00 01 and homeowners liability.
- A claims-made policy is triggered by a claim first made during the policy period and on or after the retroactive date — common for E&O, D&O, and medical malpractice (ISO CG 00 02).
- The retroactive date sets the earliest covered loss; losses before it are never covered under that claims-made policy.
- Extended Reporting Periods (the basic mini-tail and supplemental tail) cover claims reported after a claims-made policy ends, for losses on or after the retroactive date.
- Claims-made starts cheap (year-one is low-exposure) and matures; occurrence costs more up front but avoids tail-coverage gaps when switching carriers.
What a Coverage Trigger Does
A coverage trigger is the event that determines which policy period must respond to a loss. The distinction matters most for long-tail liability — injuries or errors that surface years after the act — and is among the most tested casualty topics on the national exam.
Occurrence Trigger
An occurrence policy is triggered when the bodily injury or property damage happens during the policy period, regardless of when the claim is reported. The standard Insurance Services Office (ISO) Commercial General Liability (CGL) Coverage Form, CG 00 01, is written on an occurrence basis, as is homeowners personal liability (Coverage E).
Scenario: A contractor installs a faulty railing in 2024 under an occurrence CGL. A visitor is injured in 2027 after that policy expired. The 2024 policy responds because the injury arose from work performed while it was in force — the policy that was active when the occurrence took place.
Trap: Under occurrence coverage, the report date is irrelevant. As long as the injury happened during a covered period, that period's limits apply even years later.
Claims-Made Trigger
A claims-made policy is triggered when a claim is first made during the policy period — and the loss occurred on or after the retroactive date. ISO offers a claims-made CGL (CG 00 02), but the form is most common in errors and omissions (E&O), directors and officers (D&O), and medical malpractice.
Two Conditions Must Both Be Met
- The claim is reported during the policy period (or any extended reporting period).
- The wrongful act occurred on or after the retroactive date.
Retroactive Date
The retroactive date is the earliest date a covered loss can occur. Anything before the retroactive date is never covered under that policy. Advancing (moving forward) a retroactive date when renewing creates a dangerous coverage gap, so agents fight to keep it unchanged.
Extended Reporting Periods ("Tails")
Because a claims-made policy only responds while it is in force, the insured needs protection for claims reported after the policy ends for acts that occurred during it.
| Tail | Also Called | Key Features |
|---|---|---|
| Basic ERP | Mini-tail / midi-tail | Automatic, no extra premium; short window (e.g., 60 days to report, up to 5 years for losses already incurred) |
| Supplemental ERP | Full tail | Purchased; can be unlimited in time; preserves coverage for late-reported claims |
A supplemental Extended Reporting Period (ERP) is critical when a professional retires or switches carriers, so that claims surfacing years later still have a home.
Cost and Selection Logic
| Factor | Occurrence | Claims-Made |
|---|---|---|
| Trigger | Injury happens in term | Claim reported in term |
| Year-one premium | Higher | Lower (low first-year exposure) |
| Maturity | Stable | Premium rises over ~5 years to "mature" |
| Gap risk on switch | Low | High without tail coverage |
Worked example: A consultant carries a claims-made E&O policy with a 2022 retroactive date. In 2026 a client sues over advice given in 2021. The claim is denied — the 2021 act predates the 2022 retroactive date, so it is outside coverage even though the claim was reported during the policy term. Had advice been given in 2023 and reported in 2026, the current policy (or a tail) would respond.
Exam takeaway: occurrence = when it happened; claims-made = when it was reported, on or after the retro date. Tails fill the reporting gap, and the retroactive date is the line in the sand for what is ever covered.
Why Carriers Use Claims-Made
For long-tail professional exposures, claims-made lets insurers reserve and price more accurately because the policy year that pays is the year the claim is filed, not a distant year of unknown losses. That predictability is why malpractice and management-liability lines almost universally use the claims-made trigger.
Prior Acts and "Nose" Coverage
When a professional switches carriers, the new claims-made policy can either keep the prior retroactive date (covering past acts) or set a fresh one. Maintaining the prior date is called prior-acts or "nose" coverage, and it eliminates the gap a tail would otherwise be needed to fill.
| Approach | What It Does | When Used |
|---|---|---|
| Tail (ERP) | Covers claims reported after the old policy ends | Leaving coverage / retiring |
| Nose / prior-acts | New insurer accepts the old retroactive date | Switching to a new claims-made carrier |
Trap: an insured needs either a tail on the expiring policy or nose coverage on the new one — not both. Buying tail coverage and also obtaining prior-acts on the new policy duplicates protection.
Step Factors and Maturity
A claims-made policy is inexpensive in year one because few claims can yet be reported. Premiums rise each year through a step factor until the policy matures (typically around the fifth year), after which the rate stabilizes near an occurrence-equivalent level.
Worked example: A first-year claims-made malpractice premium might be roughly 30 percent of the mature rate, a second-year about 60 percent, and a third-year about 80 percent, reaching 100 percent at maturity. This rising pattern explains why claims-made looks cheap at inception but is not truly cheaper over time.
Choosing the Right Trigger
- For short-tail exposures where injury and claim are close in time, the trigger rarely matters and occurrence is simplest.
- For long-tail professional exposures, claims-made with a stable retroactive date and proper tail/nose planning is standard.
- Always confirm the retroactive date never advances at renewal; an advanced date silently strips coverage for earlier acts.
Under an occurrence-basis CGL, a faulty railing installed in 2024 injures a visitor in 2027 after that policy has expired. Which policy responds?
A claims-made E&O policy has a 2022 retroactive date. In 2026 a client sues over advice the insured gave in 2021. What is the result?
What does a supplemental Extended Reporting Period (tail) provide on a claims-made policy?