The National Association of Insurance Commissioners (NAIC) has published market share data indicating the degree of market concentration in property/casualty insurance.
The 2015 market share data for property/casualty insurers include countrywide direct written premium for the top 25 groups and companies as reported on the State Page of the annual statement for insurers that report to the NAIC.
The full NAIC property/casualty report contains cumulative market share data for the following lines of business: personal auto, commercial auto, workers’ compensation, medical professional liability, homeowners and other liability (excluding auto liability) insurance.
NAIC said the report will be refreshed daily through March 4 and then on each Monday through the end of March and will be made available this summer.
The link below is to an abbreviated version of the full NAIC report.