8.3 Occurrence vs. Claims-Made Triggers

What "Trigger" Means

The coverage trigger is the event that determines which policy responds to a loss. For liability, the two competing systems are occurrence and claims-made. The distinction matters most for losses with a long lag between the act and the claim (e.g., products, construction defect, pollution, medical malpractice). The ISO Commercial General Liability program (form CG 00 01 occurrence; CG 00 02 claims-made) offers both.

Occurrence Trigger

An occurrence policy responds if the bodily injury or property damage takes place during the policy period — regardless of when the claim is finally reported, even years later. The policy in force when the injury happened pays.

• Simpler for the insured; no gap risk after the policy ends.
• A retired or canceled occurrence policy still covers later-discovered claims for injuries that occurred while it was active (this is why old aggregate limits still matter).

Claims-Made Trigger

A claims-made policy responds only if the claim is first made against the insured during the policy period (and, in modern ISO forms, the injury occurred on or after the retroactive date). Two dates control coverage:

• Retroactive date — injuries before this date are never covered, no matter when the claim is made.
• Extended reporting period (ERP / "tail") — extends the time to report claims after the policy ends, protecting against the gap when switching to occurrence or retiring.

Claims-Made "Maturity" and Tail Coverage

Claims-made coverage matures over successive renewals as the retroactive date stays fixed while the policy period advances, widening the covered window. When an insured switches from claims-made to occurrence, or retires, an Extended Reporting Period prevents a coverage gap:

• Basic (mini) tail — automatic, short window (often 60 days to report) plus a longer period (often 5 years) for claims from incidents already reported.
• Supplemental tail — purchased, unlimited reporting time for the retro period; carries an extra premium.

Step-Up Retroactive Dates and Coverage Gaps

When an insured renews a claims-made policy with a new (later) retroactive date, a coverage gap opens: injuries between the old and new retro dates are now orphaned — the expired policy is gone and the new one bars them as pre-retro. Best practice on the exam is to keep the original retroactive date through every renewal so the covered window only widens.

• Nose coverage (prior acts) — when switching insurers, the new claims-made carrier can agree to honor the old retro date, picking up prior acts so no tail is needed.
• Laser — an insurer may exclude a specific known claimant or matter by endorsement rather than tail the whole policy.

Worked Trigger Example

A claims-made policy runs 2024 with a 2020 retro date. A patient injured in 2019 sues in 2024.

• Injury (2019) is before the retro date (2020), so the claim is barred — no coverage, even though the claim is made during the policy period.
• Had the injury occurred in 2021 (after retro) and the claim been made in 2024 (within the period), it would be covered.

The two-part test — injury on/after retro and claim first made in period — is the single most-tested claims-made concept.

Which Lines Use Which Trigger

The exam expects you to assign the trigger by line of business. Occurrence is standard for CGL (CG 00 01), BOP, and commercial auto — exposures where the injury date is usually clear and near the claim. Claims-made dominates medical malpractice, D&O, E&O/professional liability, and EPLI — long-tail exposures where claims surface years after the act, so insurers want to control which year's policy responds.

The Tail Decision at Retirement

A physician retiring after years of claims-made coverage has three choices to avoid a gap: (1) buy a supplemental ERP (tail) from the current insurer for unlimited future reporting of past acts; (2) negotiate prior-acts (nose) coverage from a new insurer if still practicing elsewhere; or (3) accept a gap. Most retiring professionals buy the tail because a malpractice claim can arrive long after the last patient. Recognizing that tail = report future claims for past acts while nose = new insurer covers past acts is the decisive distinction.

Trigger Theories for Long-Tail Claims

When injury develops over years (asbestos, pollution), courts apply trigger theories to decide which occurrence policy responds: exposure (policy in force when exposure began), manifestation (when the injury became apparent), continuous/triple trigger (every policy from exposure through manifestation responds). These theories matter because multiple occurrence policies — and their stacked aggregates — may be on the hook. The continuous-trigger idea explains why old occurrence aggregates still matter decades later.

Why Insurers Prefer Claims-Made for Long-Tail Lines

Claims-made lets the insurer close the books at the end of each period for claims not yet reported, making long-tail exposures (med-mal, professional, D&O) far easier to reserve and price. Occurrence coverage leaves the insurer exposed to IBNR (incurred-but-not-reported) claims for years. This reserving logic is the underwriting reason the exam attaches claims-made to professional lines.