Revenues are recorded with a credit and contribute to stockholders' equity. Investors expect returns through dividends or capital gains, such as when a stock's value increases from the purchase price to the sale price.
Revenues increase net income and retained earnings, so revenues are recorded with a credit, just like all increases in stockholders' equity. When a firm issues stock, it recognizes that investors expect a rate of return, which can be via a dividend or through a capital gain. For example, buying a share of stock in Wal-Mart for $45 and selling it for $60 results in a $15 capital gain, representing an increase in the value of the stock between the purchase and sale.