A tail, or Extended Reporting Period (ERP), gives more time to make a claim after a claims-made policy ends. It does not extend the policy period. The injury must still happen after the retroactive date and before the policy ended; an injury after the policy ended is not covered just because the claim arrives during the tail.

An ERP becomes available when a gap in coverage appears: the policy is canceled or not renewed, the insurer advances the retroactive date, or the policy is replaced by an occurrence policy. A renewal that keeps the same retroactive date creates no gap, so no ERP is needed.

The Basic ERP (BERP) is built into the standard form. It begins when the policy period ends and applies automatically, at no added charge, when the policy is canceled or not renewed. It has two parts: - Mini-tail: 60 days after the policy ends for a claim from any occurrence, even one never reported to the insurer. - Midi-tail: 5 years after the policy ends for claims from occurrences reported to the insurer no later than 60 days after the policy ended. The BERP does not increase or reinstate limits: only what is left in the aggregate is available.

The Supplemental ERP (SERP), or maxi-tail, is optional. The insured must request it in writing within 60 days after the policy ends and pay an added premium, capped at 200% of the annual premium. It begins when the BERP ends, runs for an unlimited time, and comes with a fresh aggregate limit.