The significance and limitations of financial statements arise in part from the rules or principles of accounting which determine their construction. These rules grew from customs found most generally useful in trade and finance. One basic principle is that assets should reflect cost rather than current market value in order to avoid showing unrealized profits from appreciation. This rule is modified by allowances for value losses where some systematic basis for estimate exists, as in the case of depreciation of machines and buildings, bad debt losses, and the depletion of oil wells and mines. This cost rule is commonly suspended when current assets have a market value below cost at the date of the balance sheet. The current assets are those assets that turn into cash in the course of ordinary operation within a year (longer in a few industries) and typically include cash, marketable securities, customers’ indebtedness, and inventories. Marketable securities and inventories are commonly valued at whichever is lower, cost or market, partly as a matter of conservatism, which is itself almost an accounting principle. This practice is also a matter of recognizing a value loss that reduces current debt-paying power. The measurement of this ability is a central object of statement analysis. Fixed assets, such as plant or long-term security investments not likely to be sold to meet debt, are commonly shown at cost and ignore market value fluctuations on the assumption that such fluctuations are not important to the “going concern.” Appraisal and revaluation of the fixed assets are not common practice.

Many special accounting rules arise from trade customs, governmental regulations, and tax laws. They often apply only to the statements of special kinds of businesses, such as manufacturing, merchandising, railroads, public utilities, commercial banks, life, fire, and casualty insurance, and holding companies. Because practice varies greatly, typical forms and terminology are not consistent in these various fields.

Balance sheets and earnings statements may be analyzed comparatively or internally. In comparative analysis, changes in successive balance sheets or earnings statements—yearly, quarterly, or monthly—are studied for tendencies and trends. These changes may reflect long-term growth or decline of the particular business or the industry of which it is a part, or they may represent cyclical, seasonal, or special fortuitous factors. Correct understanding of the nature of the influences at work is as important as the facts of change.

Internal analysis examines the relationships or ratios between various items in the statements. The simplest devices are the percentage balance sheet, which compares each of the assets and liabilities as a percent of total assets, and the percentage income statement, where the various operating income and expense items are shown as percentages of the gross revenues or sales. Ratios are studied to discover probable liquidity or solvency and profitability or efficiency. Two common liquidity tests are the current and the quick ratios. The former is the ratio of current assets to current liabilities; the latter is the ratio of cash and equivalent plus customers’ debts (receivables) to the current liabilities. Comparisons of annual sales volume to the customers’ debts and to inventories give an idea as to their liquidity and also how efficiently the capital invested in those forms is being used to produce profits. Comparisons of indebtedness to the owners’ investment indicates something of the risk of insolvency that is being assumed. Comparisons of the cost of goods sold and the various expenses to revenues may be studied from year to year and between companies in the industry to ascertain relative efficiency and profitability. The amount of earnings relative to the investment of creditors and owners provides another measure of profitability, which, however, requires greater care in interpretation because of changing prices and the failure of the balance sheet to reflect current property values.

Although financial statements are most important to those immediately concerned with the financial fortunes of the particular business, they are read and used by others. They are used for economic analysis; for studies of business conditions; for shaping political and legislative policies; for governmental regulation; and for background information for settling labour disputes. Misinterpretation is easy here as it is in all forms of statistical abstraction. Price level changes are an especially disturbing factor. In spite of such limitations, financial statements perform a useful economic service by making possible a more intelligent assumption of business risks; directing capital into more economic channels; and improving the quality of business management and of competition. They also serve a wider social purpose in providing one more kind of information useful in evaluating political and social policies.