Due to their focus on financial stability, security market valuations and their fundamentals, such as company earnings, are of interest to investors, company finance managers, and central banks. Identifying the key financial ratios, which can predict stock market valuation levels, is crucial. This study studies relative stock market valuations, i.e., Price-Earnings, Price-Sales, Price-Book value, and Dividends-Price ratios, during the period 2001–2017. Firstly, the predictive CHAID decision tree algorithm is applied to investigate the relative importance and impact of 29 financial ratios on market valuations. Secondly, regression analysis is used to study whether the growth of two earnings measures, i.e., sales and net income, can justify the market valuations. The implications for computerized risk management are discussed, and future research opportunities are mentioned.