ILWs sit between traditional indemnity reinsurance and index-based insurance-linked securities. They can be relatively simple to describe—“pay if industry loss exceeds X”—but the details of the trigger, event definition, loss-reporting source and buyer’s own loss condition determine whether the hedge works as expected.
How an ILW trigger works
Artemis defines ILWs as protection based on total insured industry losses from a specified event. For example, a reinsurer exposed to U.S. hurricane risk might buy an ILW that attaches when the market-wide insured loss from a qualifying storm exceeds a stated dollar threshold.
The contract specifies a limit, covered peril, territory, event period and the source or methodology used to determine the industry loss. Once the contractual conditions are satisfied, the protection amount is determined by the ILW terms rather than by adjusting every underlying policy loss in the buyer’s portfolio.
Single trigger vs. double trigger
Some ILWs use only an industry-loss or index condition. Others add an indemnity condition requiring the buyer to have sustained a minimum amount of loss from the same event. The second condition can help establish an insurable interest and align the contract more closely with the buyer’s actual catastrophe experience.
| Structure | Main trigger | Main trade-off |
|---|---|---|
| Indemnity reinsurance | Buyer’s actual covered losses | Closer match to portfolio loss, but requires detailed loss adjustment |
| Industry Loss Warranty | Industry-wide loss threshold, sometimes plus buyer-loss condition | Simple external trigger but introduces basis risk |
| Parametric protection | Physical parameter such as wind speed or earthquake intensity | Fast objective trigger but can diverge from insured loss |
| Catastrophe bond | Can use indemnity, industry, parametric or modeled triggers | Multi-year capital-markets structure with higher transaction complexity |
Why insurers and reinsurers buy ILWs
- To add catastrophe protection above a broad market-loss threshold.
- To supplement a traditional reinsurance or retrocession tower.
- To hedge peak-zone exposure when additional indemnity capacity is limited.
- To obtain protection during an active season or after market conditions change.
- To diversify sources of capacity between traditional and collateralized markets.
What is basis risk?
Basis risk is the possibility that the industry index and the buyer’s own losses do not move together. A company can suffer a large portfolio loss while the industry total stays below the ILW trigger, producing no payment. The reverse can also happen: the industry threshold can be met even though the buyer’s own loss is relatively small, unless the contract contains a buyer-loss condition.
Territory, peril definition, market share, index methodology and attachment point all affect basis risk.
Why the industry-loss source matters
Catastrophe loss estimates develop over time. Early estimates can be revised as claims emerge, and different data providers can use different scopes and methodologies. ILW drafting therefore needs to identify the recognized reporting source, calculation date, qualifying event and how revisions are handled.
ILWs and the ILS market
ILWs can be provided by traditional reinsurers or collateralized capital and can be structured as reinsurance or, in some settings, derivative-style protection. Artemis tracks ILW pricing as one indicator of catastrophe reinsurance and retrocession market conditions. Industry-loss triggers are also used in some catastrophe bonds and other insurance-linked securities.
Frequently asked questions
Is an ILW the same as a catastrophe bond?
No. Both can use an industry-loss trigger, but a catastrophe bond is a securitized capital-markets transaction, while an ILW is typically a private reinsurance, retrocession or derivative-style contract.
Does an ILW always require the buyer to have a loss?
Not always. Some contracts contain an additional indemnity or buyer-loss trigger, while others rely primarily on the industry index. The wording determines the requirement.
Why would a buyer choose an ILW instead of indemnity reinsurance?
ILWs can provide flexible catastrophe hedging and access to additional capacity, but the buyer accepts basis risk because the trigger is not solely its own adjusted loss.
Can ILWs cover risks other than hurricanes?
Yes. Industry-loss triggers have been used for earthquake and other catastrophe risks, and the concept has expanded into additional indexed risk-transfer applications.
Sources & further reading
Reviewed October 3, 2026. ILW triggers, industry-loss sources, buyer-loss conditions and legal form vary by transaction.
