8.3 Occurrence vs. Claims-Made Triggers

What a Coverage Trigger Is

A coverage trigger is the event that determines which policy responds to a loss. Liability lines use two triggers, and distinguishing them is one of the most heavily tested casualty topics.

Trap: On an occurrence form, when the claim is filed is irrelevant — what matters is when the injury occurred. A 2026 occurrence policy covers a 2026 injury even if the lawsuit arrives in 2031.

The Occurrence Trigger

An occurrence is defined in the CGL as "an accident, including continuous or repeated exposure to substantially the same general harmful conditions." The trigger is the date injury or damage occurs, not when the negligent act happened or when the claim is reported. This produces the long-tail problem: injuries from products or pollution may surface years later, yet the policy in force at the time of injury must respond. Insurers must hold reserves for decades, which is why some lines moved to claims-made forms.

Worked Example — Occurrence

A contractor installs a defective beam in 2024 (occurrence form in force). The beam fails and injures a tenant in 2028; suit is filed in 2030. The 2024 occurrence policy is triggered (most courts use injury-in-fact), and the 2030 carrier is not on the risk for that loss.

The Claims-Made Trigger

A claims-made policy responds only if the claim is first made during the policy period (or extended reporting period) AND the injury occurred on or after the retroactive date. Three features are tested:

• Retroactive (retro) date — the earliest date of injury the policy will cover. No coverage for occurrences before the retro date, regardless of when the claim is made.
• Extended Reporting Period (ERP, or "tail") — extends the time to report claims after the policy ends. A Basic ERP (mini-tail) is automatic (typically 60 days to report a claim, plus 5 years for occurrences already reported); a Supplemental ERP is purchased and is unlimited in time.
• Step (maturity) factors — early claims-made years are cheaper and "mature" toward occurrence-level pricing over about five years.

Trap: A claim reported for an injury that happened before the retro date is NOT covered, even if the policy is currently in force.

Worked Trigger Comparisons

Scenario: Retroactive date 1/1/2023; claims-made policy in force for 2026. Injury occurred 6/1/2025; claim first made 3/1/2026.

• Injury (2025) is after the retro date (2023). OK.
• Claim is first made during the 2026 policy term. OK.
• Result: covered.

Variation: Same policy, but the injury occurred 6/1/2022 (before the 1/1/2023 retro date). Even though the claim is made in 2026, it is NOT covered — the injury predates the retro date.

ERP variation: The insured cancels at 12/31/2026 and buys a Supplemental ERP. A claim made in 2029 for a 2026 injury is covered, because the tail extends the reporting window indefinitely while the retro date still applies.

The Five Claims-Made Maturity Years

Claims-made pricing rises over roughly five years as the policy "matures." A first-year claims-made policy is the cheapest because, with a retro date equal to the inception date, it can only be hit by claims arising from injuries during that single year. Each renewal pushes the retro date back another year of covered exposure, so by the fifth year the policy behaves much like an occurrence policy in cost.

This step-rating is why an insured who switches carriers must protect the gap: a new claims-made policy with a fresh retro date will not cover injuries from the prior years, making the extended reporting period or a matching retro date on the new policy essential.

Reporting Periods Compared

Distinguish the two tails carefully. The Basic ERP is automatic and free but limited: it gives a short window (commonly 60 days) to report claims arising from occurrences already known, plus a longer window (commonly five years) to report claims for occurrences reported to the insurer during the policy term.

The Supplemental ERP must be purchased, usually within 60 days of expiration, and provides an unlimited time to report claims for injuries that occurred between the retro date and the policy's end. Neither tail moves the retro date - injuries before the retro date are never covered - so the tail only extends reporting time, not the range of covered injury dates.

Why Lines Choose One Trigger Over the Other

Occurrence triggers dominate stable, short-tail exposures (auto, homeowners, premises liability) where the injury and claim arrive close together. Claims-made triggers dominate long-tail professional exposures - E&O, D&O, medical malpractice - where harm may not surface for years and insurers want to know their exposure as claims arrive rather than decades later. Understanding this rationale helps you predict the trigger a question implies even when it is not stated: a malpractice or professional-liability scenario almost always involves a claims-made analysis with a retro date and tail.