Definition:Per-occurrence loss
📋 Per-occurrence loss is the total amount of insured loss attributable to a single event or occurrence, aggregated across all affected policies and claims within an insurer's or reinsurer's portfolio. In insurance and reinsurance practice, this figure is the essential building block for triggering per-occurrence excess of loss recoveries, testing retention adequacy, and reporting to rating agencies and regulators after a major event.
⚙️ Calculating a per-occurrence loss starts with defining the boundaries of the occurrence itself. Contract language — particularly the hours clause in catastrophe treaties — specifies the time window and geographic scope within which individual claims can be grouped into a single occurrence. An insurer hit by a Category 4 hurricane, for instance, aggregates all property and business interruption claims caused by that storm into one per-occurrence loss total. The accuracy of this aggregation directly determines whether reinsurance recoveries attach and how much the cedent retains net. Loss adjustment expenses may or may not be included in the per-occurrence calculation depending on treaty wording.
💡 Getting the per-occurrence loss figure right has profound financial consequences. An undercount can leave recoverable reinsurance on the table; an overcount — or the improper merging of two distinct events into one — invites coverage disputes. After large natural catastrophes, the industry often spends months refining occurrence loss estimates as claims develop and courts interpret policy wordings. Catastrophe modelers produce per-occurrence loss distributions that feed directly into an insurer's probable maximum loss calculations and inform how much reinsurance to purchase. In short, the per-occurrence loss is not merely an accounting output — it is the pivot around which risk transfer decisions and capital allocation revolve.
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