Tenure of the insurer–reinsurer relationship and underwriting performance: evidence from the US property-casualty insurance industry

Abstract This study analyses National Association of Insurance Commissioners data on US property-casualty insurers from 2010 to 2020 using a one-step system generalised method of moments model. We examine the correlation between the duration of insurer–reinsurer relationships and underwriting performance, with relationship depth measured by historical reinsurance premiums. The findings are consistent with the asymmetric learning, real service, and monitoring hypotheses, suggesting that insurers begin to realise the benefits of reinsurance relationships only after approximately 3 years, particularly in the case of single unaffiliated insurers. This study underscores the significance of long-term reinsurance relationships for underwriting, proposes strategies for sustainable development, and offers practical insights for stakeholders.