Category: Parametric insurance · Reviewed by Jake Leat, Associate Director · Last reviewed 2026-06-10
Basis risk in parametric insurance is the risk that the contractual payout, calculated by reference to a defined index, does not correspond to the policyholder’s actual economic loss. It is the principal commercial issue with the form, the principal reason for retail consumer protection scrutiny, and the focus of the European Insurance and Occupational Pensions Authority’s 2023 Discussion Paper on parametric insurance.
Category: Parametric insurance Also known as: Basis risk, parametric basis risk, trigger basis risk Established / Coined: Term in regular use from the early 2000s in weather risk management Related concepts: Parametric insurance, Trigger event parametric, Consumer Duty, ICOBS
Basis risk in a parametric contract has three principal sources:
Two further forms are commonly identified: structural basis risk (the index does not capture the right physical phenomenon — e.g. wind speed at 10 m height not capturing the gusts that damaged the structure) and counterparty basis risk (a different agency reports the trigger value than the one the parties anticipated).
Basis risk has three legal dimensions in the United Kingdom. First, ICOBS 5 (suitability) and ICOBS 6 (information requirements) require brokers and insurers to give clear and timely information about the limitations of the cover, and basis risk in a parametric contract is such a limitation. The Consumer Duty (FCA PS22/9) and PROD 4 product governance require fair-value assessment that includes consideration of how foreseeable customers might experience non-payout despite suffering loss.
Second, the St Christopher test ([1974] 1 WLR 99) and Marine Insurance Act 1906 s.4 require insurable interest; very wide basis risk approaching independence between trigger and loss may move the contract into derivative territory under article 83 of the FSMA 2000 (Regulated Activities) Order 2001 — the central concern of the EIOPA Discussion Paper on parametric insurance (June 2023).
Third, PRA SS5/16 requires Solvency II internal models to evidence the correlation between trigger and underlying loss for capital purposes; weak correlation may force a higher capital charge or a refusal to recognise the parametric as a risk-transfer instrument for solvency.
Basis risk is quantified by historical back-testing: the contractual payout is calculated over a historic event set and compared with the policyholder’s historic actual losses. Standard back-testing metrics include the correlation coefficient between payout and loss, the conditional payout-given-loss probability, and the “Hit/Miss” matrix (events triggered with no loss; losses incurred with no trigger). EIOPA’s 2023 paper recommends back-testing methodology to be disclosed to retail consumers.
Mitigation techniques include: choice of more granular index data sources (e.g. site-installed sensors for FloodFlash rather than river gauges); multi-station composite indices; finer trigger calibration (more tiers, lower binary jumps); and hybrid parametric-indemnity structures where the parametric layer pays cash quickly and an indemnity layer fills the gap.
The EIOPA Discussion Paper on parametric insurance (June 2023) identifies basis risk as the single largest consumer-protection concern in retail parametric and proposes supervisory expectations including: standardised disclosure templates; back-testing reporting; clear product-name labelling distinguishing parametric from indemnity; and prohibition of misleading marketing. The UK FCA Innovation Hub has engaged with retail parametric flood propositions on the same themes. The Lloyd’s Lab cohort 10 (2023) included projects focused on basis risk quantification and communication.
A retail UK SME purchases a parametric flood cover with a 30 cm depth trigger at a site-installed sensor. In a flood event the sensor records 28 cm and the policy does not pay; the policyholder has nevertheless suffered GBP 50,000 of damage. The MGA’s PROD 4 fair-value assessment is updated to capture this near-miss scenario and the wording is revised in the following renewal cycle to add a 20 cm tier paying 50% of the limit. The broker’s records show the basis-risk disclosure given at the original sale and the policyholder’s acknowledgement under ICOBS 5.
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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