Definition:Per occurrence excess of loss
📋 Per occurrence excess of loss is a reinsurance structure in which the reinsurer indemnifies the ceding company for the portion of loss from a single occurrence that exceeds a specified retention (also called the attachment point), up to a defined limit. It is one of the most widely used forms of excess of loss reinsurance, providing protection against the severity of individual events rather than the cumulative frequency of losses over time. This structure is central to catastrophe reinsurance programs as well as per-event casualty protections across every major insurance market.
⚙️ A per occurrence excess of loss treaty is structured in layers, each with its own attachment point and limit. For example, a cedent might retain the first $10 million of any occurrence and purchase reinsurance that covers $15 million in excess of $10 million — meaning the reinsurer pays for losses between $10 million and $25 million attributable to a single event. Multiple layers can be stacked to extend protection further, with different reinsurers participating at different levels of the tower. When a qualifying occurrence produces aggregate losses that breach the retention, the cedent files a claim against the applicable layer. The occurrence definition and any hours clause embedded in the treaty determine how individual losses from a widespread event — such as a hurricane or earthquake — are grouped into a single occurrence for purposes of calculating recovery. Reinstatement provisions typically apply, allowing the cedent to restore exhausted limits after a loss by paying an additional premium.
💡 Per occurrence excess of loss treaties are indispensable for managing peak exposures. They protect an insurer's balance sheet against outsized single-event losses that could otherwise impair solvency, and they do so without requiring the cedent to share premium and profit on every risk in the portfolio, as a proportional treaty would. Pricing these treaties demands rigorous catastrophe modeling and actuarial analysis, incorporating factors such as historical loss experience, modeled probable maximum loss scenarios, and the cedent's geographic and line-of-business concentrations. Regulatory regimes around the world — Solvency II in Europe, the RBC framework in the United States, and C-ROSS in China among them — grant capital credit for qualifying per occurrence excess of loss protections, reinforcing their strategic value in enterprise-level capital optimization.
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