Liability insurance operates on one of two fundamental triggering mechanisms, and understanding the difference between them is essential for anyone advising clients, managing organizational risk, or purchasing coverage for their own operations. The occurrence basis, which forms the subject of this lesson, represents the traditional approach to liability insurance and remains the dominant form for many classes of commercial and personal coverage across Canada. Under an occurrence policy, the insurer agrees to respond to claims arising from incidents that take place during the policy period, regardless of when the injured party actually brings forward their claim. This seemingly straightforward concept carries profound implications for insureds, insurers, and the professionals who work with both, particularly when claims emerge years or even decades after the underlying events that caused them.
The conceptual foundation of occurrence coverage rests on the principle that the policy in force at the time of the harmful event governs the claim. If a customer slips and falls in a retail store on March 15, 2024, the occurrence policy in effect on that date will respond to any resulting claim, whether the lawsuit arrives six months later or six years later. This approach provides insureds with a form of permanent protection for past conduct, so long as they maintained continuous coverage during the periods when potentially harmful events occurred. The insured purchases a policy for a specific term, typically twelve months, and that policy then stands as a permanent record of coverage for anything that happened during that period. Even if the insured later cancels their coverage entirely, the old occurrence policy remains available to respond to claims arising from covered incidents during its term.