Category: Parametric insurance · Reviewed by Amy Price, Account Executive · Last reviewed 2026-06-10
Trigger event parametric is the technical term for the architecture by which a parametric insurance contract identifies the circumstance that gives rise to a payment obligation. Triggers may be single-parameter, multi-parameter, cascade, “cat-in-a-box”, modelled-loss or industry-loss-warranty hybrid; their design is the principal underwriting question in parametric structuring and the principal source of basis risk for the policyholder.
Category: Parametric insurance Also known as: Trigger event, parametric trigger, cat-in-a-box, modelled loss trigger Established / Coined: Trigger architectures from late-1990s catastrophe bond market Related concepts: Parametric insurance, Basis risk parametric, Catastrophe bond, Industry loss warranty
A trigger event in a parametric contract is the defined factual circumstance, expressed as one or more measurable conditions, the occurrence of which gives rise to the insurer’s payment obligation. The four principal trigger architectures used in commercial parametric and ILS structuring are:
For a contract to be insurance under English law the St Christopher test ([1974] 1 WLR 99) and Prudential ([1904] 2 KB 658) require, among other elements, that the insured has an interest in the subject matter — Marine Insurance Act 1906 s.4 for marine/property risks, Life Assurance Act 1774 s.1 for life and personal accident analogues. A trigger event clause that pays without reference to the insured’s economic exposure may, depending on construction, be characterised as a derivative under article 83 of the FSMA 2000 (Regulated Activities) Order 2001. UK practice — and the EIOPA Discussion Paper on parametric insurance (June 2023) — treats parametric contracts as insurance where the buyer has insurable interest and the contract pays an amount not greater than the indemnity that would otherwise be payable.
PRA SS5/16 addresses the prudential treatment of triggers under Solvency II internal models, requiring that the modelled correlation between trigger and loss be evidenced and stress-tested. The Insurance Act 2015 s.11 (terms not relevant to the actual loss) is relevant where the trigger functions as a condition precedent.
Trigger calibration is undertaken by combining catastrophe model output, historical event data, the policyholder’s exposure footprint and risk appetite. RMS HD, KCC and Verisk AIR (the three principal commercial cat models in the London market) provide event-set simulations from which expected loss and exceedance probability are estimated. Triggers are calibrated to a defined return period (commonly 1-in-50, 1-in-100 or 1-in-250-year events). The reporting agency (USGS for earthquake, US National Hurricane Center for North Atlantic hurricane, Met Office or ECMWF for European weather) is contractually fixed.
Cascade trigger structures combine a parametric first-loss with an indemnity drop-down — for example, a parametric trigger pays USD 10 million within 30 days and a traditional indemnity layer responds for losses above that figure once adjusted. Modelled-loss triggers use a “reference model” agreed in the slip, with the calculation done by the modeller’s claims service.
Post-2020, hybrid trigger structures combining cat-in-a-box plus magnitude (double-trigger) have become common in earthquake parametric to reduce basis risk. Multi-step triggers (payout tiered by intensity) and seasonal aggregate triggers (cumulative rainfall over a defined period) are used in agricultural index insurance and ILS.
A London market MGA writes a parametric hurricane contract for a Florida hotel chain. The trigger is: (i) a hurricane of Saffir-Simpson category 3 or higher; (ii) eye passing within 50 nautical miles of any insured property (cat-in-a-box); and (iii) sustained wind speed of at least 111 mph recorded by the nearest National Weather Service station. On trigger, the policy pays a tiered amount: USD 5 million at Category 3, USD 10 million at Category 4, USD 15 million at Category 5. Settlement occurs within 21 days of National Hurricane Center post-event analysis.
This entry is part of the Apex Insurance Wiki. Last reviewed by Matt Bartlett on 2026-06-10. Next review: 2026-12-10.
Apex Insurance Brokers Limited. Authorised and regulated by the Financial Conduct Authority, FRN 724952. Registered in England and Wales, Companies House 07014570. This entry provides general information about UK insurance concepts and is not regulated advice. Consult your insurance broker on your specific position.
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