Actuarial Analysis of Catastrophe Bond Structures for Nigerian Flood and Storm Risk

This study conducts an actuarial analysis of catastrophe bond structures as a mechanism for transferring Nigerian flood and storm risk to international capital markets. Catastrophe bonds provide insurance-linked securities that transfer specified disaster risk to bond investors in exchange for above-market coupon payments, with principal at risk if a defined catastrophic event occurs. Given the limited domestic reinsurance capacity for large-scale natural disaster losses in Nigeria, cat bond structures offer an alternative risk transfer channel that could complement traditional reinsurance. This study develops a probabilistic catastrophic flood and storm loss model for Nigeria using hydrological data from the National Emergency Management Agency and the Nigerian Hydrological Services Agency for 2010 to 2023, combined with property exposure data from urban land use surveys in Lagos, Port Harcourt, and Kano. Annual exceedance probability curves are constructed for flood and wind losses at the national level. Cat bond trigger structures including indemnity, parametric, and modeled loss triggers are evaluated for Nigerian applicability. Findings reveal that parametric triggers based on river gauge height and wind speed measurements provide a technically viable and low-basis-risk trigger mechanism for Nigerian cat bonds. The expected loss for a 1-in-50-year flood event in Lagos State is estimated at 85 billion naira, within the range of viable cat bond transaction sizes. The study concludes that Nigerian catastrophe bonds are technically feasible and recommend that the Federal Government explore a sovereign cat bond transaction for flood risk.

Keywords: catastrophe bonds, flood risk, insurance-linked securities, parametric trigger, Nigeria.