Claims Occurred

The vast majority of insurance policies are sold on a Claims Occurred / Occurences basis. This means that the claim is covered by the policy which was in force at the time of the incident which caused the claim. In most cases this will be the current or previous year's policy, however for long-tail risks (e.g. asbestosis claims under employer's liability) this could be a policy written decades ago.

The alternative mechanism is Claims Made.