This paper analyzes the accuracy of the risk-based capital formula for property-liability insurers that was adopted in 1993 by the National Association of Insurance Commissioners (NAIC). A logit analysis is conducted on a large sample of solvent and insolvent insurers spanning the period 1989–1993. Predictive accuracy is very low when the ratio of NAIC risk-based capital to actual capital is the sole indendent variable in the logit analysis, but accuracy improves significantly when the components of the formula and variables for firm size and organizational form are used as regressors. Improvements in the formula are needed to facilitate prompt corrective action and reduce insolvency costs.