8.3 Occurrence vs. Claims-Made Triggers

The Coverage Trigger Problem

Liability claims often surface years after the negligent act — think of slowly developing pollution, defective products, or professional errors. The coverage trigger answers the question: which policy year responds? The ISO Commercial General Liability form comes in two trigger versions, and confusing them is one of the most heavily tested casualty topics.

• Occurrence form — CG 00 01 — covers injury or damage that occurs during the policy period, no matter when the claim is later reported.
• Claims-made form — CG 00 02 — covers claims first made during the policy period (or extended reporting period), provided the injury occurred on or after the retroactive date.

Occurrence Trigger

Under the occurrence form, the date the bodily injury or property damage happens locks in coverage. A 2026 policy responds to a 2026 injury even if the lawsuit arrives in 2031. Advantages: simple, no reporting deadline, no tail needed. Disadvantage for insurers: long-tail exposure forces them to hold reserves for decades, which is why occurrence forms cost more for hazardous classes and why claims-made forms were created for medical malpractice and other long-tail risks.

Claims-Made Trigger — Three Moving Parts

The claims-made form requires two events to align plus optional tail coverage:

1. Retroactive date — the earliest injury date the policy will cover. Injury before the retro date is never covered, even if the claim is timely. Never let the retro date advance when renewing — that creates a coverage gap.
2. Policy period — the claim must be first reported during this window.
3. Extended Reporting Period (ERP / "tail") — covers claims reported after expiration for injuries that occurred during the policy term.

ISO provides a Basic ERP (automatic, limited: typically a 60-day reporting tail plus a 5-year tail for occurrences already reported) and a purchasable Supplemental ERP with no time limit. A Basic ERP is free and automatic; the Supplemental ERP must be requested, usually within 60 days of expiration.

The Three-Step Claims-Made Test

Worked trap: a policy has a retro date of 1/1/2024 and a term of 1/1/2026-1/1/2027. An injury occurred in 2023 and the claim is made in 2026. No coverage — the injury predates the retro date, so step 1 fails even though the claim was timely reported.

Retroactive Date and Tail Coverage

For claims-made forms, two dates govern coverage and generate many questions. The retroactive date is the earliest injury date the policy will cover — anything occurring before it is excluded even if claimed during the policy period. The extended reporting period (ERP, or "tail") covers claims made after the policy ends for injuries that occurred during the active period; a basic tail is automatic and short (e.g., 60 days), while a supplemental tail is purchased for a longer or unlimited window.

Why the Trigger Matters: Long-Tail Claims

Occurrence triggers shine for long-tail exposures (asbestos, pollution, latent defects) where injury manifests years after exposure — the policy in force when the injury occurred responds, even decades later. Claims-made was developed precisely because insurers could not reserve adequately for such stacking. On the exam, match the trigger to the timeline: if a question stresses when the claim was first made and a retroactive date, it is claims-made; if it stresses when the injury happened, it is occurrence.

Reporting the Claim: Notice as a Condition

Both triggers depend on the insured satisfying the notice/duties condition. Under a claims-made form, a claim first made and reported during the policy period (or tail) triggers coverage, so prompt reporting is essential. Many claims-made forms also allow reporting a potential claim (circumstance) during the period to lock in coverage even if the actual claim arrives later. Late notice that prejudices the insurer can defeat coverage — a tested overlap between the trigger concept and policy conditions.

Batch Clauses and Trigger Theories

For mass or repeated injuries, a batch clause treats all claims arising from one root cause as a single occurrence (and one deductible/limit), important for products liability. Courts also apply trigger theories — exposure, manifestation, injury-in-fact, and continuous (triple) trigger — to decide which occurrence policies respond to long-latency harm like asbestos. The exam keeps this conceptual: know that the occurrence form's response depends on when the injury occurred, which these theories pinpoint.

Switching Forms — Avoiding the Gap

When an insured moves from claims-made to occurrence (or changes carriers), gaps open if the tail is not addressed. Two solutions:

• Tail coverage (ERP) on the expiring claims-made policy — covers late-reported claims for past injuries.
• Nose coverage (prior acts) on the new policy — sets the new retro date back to the original retro date so the new policy picks up old injuries.

Exam tip: occurrence-to-claims-made and back is fine if either the tail or prior-acts coverage bridges the period; without one, injuries that occurred but were not yet reported fall through.