An S corporation, for United States federal income tax purposes, is a corporation that makes a valid election to be taxed under Subchapter S of Chapter 1 of the Internal Revenue Code.

In general, S Corporations do not pay any federal income taxes. Instead, the corporation's income or losses are divided among and passed through to its shareholders. The shareholders must then report the income or loss on their own individual income tax returns. This concept is called single taxation; if the corporation is taxed as a C Corporation, it will face double taxation, meaning both the corporation's profits, and the shareholders' dividends, will be taxed.