Occurrence Basis

Occurrence Basis is a policy condition under which claims that meet the policy definition of a claim, will only be considered for coverage if the event that gave rise to a claim, a.k.a., the occurrence, happened during the policy period. These policies are said to have ‘long-tail liability’ because the claims can be reported at any time, even long after the policy period has ended. This is in direct contrast to policies written on a discovery basis.
Commercial General Liability (CGL) insurance is an example of an occurrence-based insurance.

See also Claims Made and Claims Made and Reported.