8.3 Occurrence vs. Claims-Made Triggers
Key Takeaways
- OCCURRENCE policies respond to injury that happens DURING the policy period, no matter when the claim is later filed — even decades later.
- CLAIMS-MADE policies respond only when the claim is FIRST made during the policy period (and after any retroactive date), regardless of when the injury occurred.
- The RETROACTIVE DATE is the gatekeeper for claims-made — injuries before it are never covered; advancing or erasing it destroys prior coverage.
- An EXTENDED REPORTING PERIOD (tail) lets claims-made insureds report later claims for prior incidents after the policy ends — basic (mini-tail) is automatic; supplemental is purchased.
- Long-tail exposures (asbestos, malpractice) drive the choice — claims-made keeps reserves current; occurrence risks 'stacking' old limits.
Two Ways a Liability Policy Is Triggered
When does a liability policy actually 'turn on'? There are two triggers, and the difference is one of the most heavily tested concepts in commercial casualty.
| Feature | Occurrence Trigger | Claims-Made Trigger |
|---|---|---|
| What activates coverage | Injury or damage happens during the policy period | Claim is first made during the policy period |
| When claim is reported | Anytime, even years later | Must be reported within the period (or tail) |
| Retroactive date | Not used | Critical — bars pre-retro injuries |
| Tail coverage | Not needed | Needed to report after expiration |
| Typical lines | CGL (standard), homeowners, auto | Most professional liability, D&O, some CGL |
The standard ISO CGL (form CG 00 01) is written on an occurrence basis; the parallel CG 00 02 is the claims-made version.
The Occurrence Trigger
An occurrence policy covers bodily injury or property damage that takes place during the policy period, regardless of when the claim is reported. If a contractor's faulty wiring in 2026 causes a fire in 2032, the 2026 occurrence policy responds.
- Advantage: No gap for late-reported claims; the insured never needs tail coverage.
- Disadvantage for insurers: Claims can surface decades later ('long-tail'), making reserving difficult and allowing multiple old policy limits to stack on a single continuous injury (asbestos).
Trap: Under occurrence, the policy in force when the injury happened pays — not the policy in force when the lawsuit arrives.
The Claims-Made Trigger
A claims-made policy covers a claim first made against the insured during the policy period, provided the injury occurred on or after the retroactive date. Two features control it:
Retroactive Date
The retroactive (retro) date is the earliest date of injury the policy will cover. Injury before the retro date is never covered, even if the claim arrives during the period.
- The retro date should stay stable when renewing; advancing it forward creates an uncovered gap, and a policy with no retro date (full prior acts) is the broadest.
Extended Reporting Period (Tail)
When a claims-made policy ends, claims for prior covered incidents may still surface. The extended reporting period (ERP), or 'tail,' lets the insured report them:
- Basic ERP (mini-tail): automatic, short (often 60 days run-off plus a 5-year reporting window for incidents already reported).
- Supplemental ERP (full tail): purchased, can be unlimited in duration.
Tail and Nose Coverage in Practice
When an insured leaves a claims-made program, the gap created by the retroactive date is closed two ways:
- Tail coverage (Extended Reporting Period, ERP): purchased from the expiring insurer, it extends the time to report claims for occurrences before the policy ended. A Basic ERP is automatic and short (a mini-tail, e.g., 60 days for any claim, plus 5 years for occurrences reported late), while a Supplemental ERP is purchased for an unlimited reporting window.
- Nose coverage (prior-acts / retroactive date): the new insurer agrees to a retroactive date matching the old policy, covering claims for past occurrences as long as they are reported during the new policy.
Long-Tail Exposures and the Trigger Battle
Claims-made forms exist because of long-tail exposures — asbestos, pollution, construction defect, and pharmaceutical injury — where the injury manifests years after the act. Courts have applied exposure, manifestation, continuous (injury-in-fact), and triple triggers to occurrence policies in these cases, which is exactly the uncertainty claims-made coverage was designed to eliminate. On the exam, if a single claim could attach to multiple policy years, that signals an occurrence-form trigger dispute; a claims-made form sidesteps it by keying on the report date.
A claims-made professional liability policy runs 1/1/2026–12/31/2026 with a retroactive date of 1/1/2024. A patient is injured by treatment given in 2023 and files suit in March 2026. Is the claim covered?
Deciding Which Policy Pays — Worked Logic
Walk the facts through this test:
- Occurrence form? Find the policy in force when the injury happened. That one pays, up to its limit, whenever the claim arrives.
- Claims-made form? Ask two questions: (a) Was the claim first made during the policy period or its tail? (b) Did the injury occur on or after the retro date? Both must be 'yes.'
Example: Injury in 2025, claim filed 2027. An occurrence policy from 2025 responds. A claims-made policy needs the 2027 policy (or a tail) plus a retro date of 2025 or earlier.
The Five Coverage Steps of a Maturing Claims-Made Program
When an insured first buys claims-made coverage and renews it year after year, ISO prices it through five maturity steps. Each renewal pushes the retro date further from the current period, so the chance of a brand-new claim that also satisfies the retro date rises — and the premium climbs until it reaches the 'mature' (5th-year) rate.
| Year | Maturity | Premium Posture |
|---|---|---|
| 1 | First-year (immature) | Lowest — narrow window of covered prior acts |
| 2–4 | Maturing | Rising each year |
| 5+ | Mature | Highest, roughly comparable to occurrence pricing |
Why it matters: A claims-made policy is cheaper than occurrence in early years (less exposure) but converges on occurrence cost as it matures. Switching carriers can reset this — and risks a retro-date gap.
Advantages, Disadvantages, and the Switching Trap
Claims-made advantages (insurer view): reserves track current claims, no decades-old 'long-tail' surprises, and limits cannot stack across many old policies for one continuous injury.
Claims-made disadvantages (insured view): the insured must keep coverage continuous, guard the retro date, and buy tail coverage to retire or switch carriers safely.
Switching Carriers Safely
When an insured moves from one claims-made carrier to another, there are two clean options:
- Nose (prior acts) coverage: the new carrier agrees to use the old retro date, covering incidents back to the original date — no tail needed.
- Tail (ERP) from the old carrier: the expiring carrier sells an extended reporting period for claims on its watch.
Trap: Buying a new claims-made policy with a new (current) retro date and no tail on the old one leaves a gap — incidents from prior years are covered by neither policy. The exam tests this gap directly.
A retiring architect cancels her claims-made policy. Which option best protects her against claims for past work that may be reported in future years?