Earnings are part of sales revenue. But sales are generated from investment assets. From a shareholder’s perspective, earnings should at least equal the required return of equity capital on the initial investment. From a firm’s point of view, it should cover the capital charge, that is, the cost of equity capital on the book value of equity. Earnings can also be generated from the firm’s goodwill and other intangible assets. Future earnings can also be affected by conservative accounting principles. Although much progress has been made in understanding how factors affect earnings generation, less progress has been made in defining the functional dependence of earnings on these factors. In this chapter, we explore the determinants of future earnings.