The long-term debt to capitalization ratio, a variation of the traditional debt-to-equity (D/E) ratio, shows the financial leverage of a firm. It is calculated by dividing long-term debt by total available capital (long-term debt, preferred stock, and common stock). Investors compare the financial leverage of firms to analyze the associated investment risk. High ratios indicate riskier investments, as debt is the primary source of financing and introduces a greater risk of insolvency.