Definition:Property catastrophe excess-of-loss reinsurance
🌪️ Property catastrophe excess-of-loss reinsurance is a form of non-proportional reinsurance that protects a ceding company against the accumulation of property claims arising from a single catastrophic event, such as a hurricane, earthquake, or wildfire. Unlike proportional treaties that share every risk on a quota basis, this structure only triggers when the cedent's aggregate losses from a qualifying catastrophe event exceed a pre-agreed retention — often called an attachment point. It sits at the heart of most reinsurance programs for insurers with significant property exposure, serving as the primary financial shield against peak natural-disaster losses.
⚙️ The mechanics revolve around a defined treaty layer expressed as a monetary band — for example, $50 million excess of $25 million — which means the reinsurer pays for losses that fall between $25 million and $75 million per event, while the cedent absorbs everything below the attachment and anything above the treaty limit (unless a higher layer exists). Reinstatement provisions govern whether coverage is restored after an event, and at what additional premium. Pricing hinges on sophisticated catastrophe models that simulate thousands of potential event scenarios to estimate expected losses, probable maximum losses, and return periods. These models, produced by vendors such as Moody's RMS, Verisk, and CoreLogic, are central to every negotiation between cedent and reinsurer, and much of the capacity is placed through the reinsurance broker market or at Lloyd's of London.
📊 For insurers that write homeowners, commercial property, or agricultural lines, securing adequate catastrophe excess-of-loss protection is often a regulatory and rating-agency expectation, not merely a strategic choice. Rating agencies like A.M. Best and S&P evaluate whether a company's net retention relative to its surplus is prudent, and inadequate cat reinsurance can trigger a downgrade. Beyond solvency protection, the product also stabilizes loss ratios year over year, enabling insurers to maintain competitive premium rates without having to hold prohibitively large reserves for tail risk. As climate volatility intensifies, capacity and pricing in this market increasingly influence which regions and perils primary insurers are willing to cover at all.
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