An S corporation may only have one class of stock. A single class of stock means that all outstanding shares of stock confer "identical rights to distribution and liquidation proceeds," i.e. profits and losses are allocated to shareholders proportionately to each one's interest in the business. § 1.1361-1(l)(1). Differences in voting rights are disregarded, which means that an S corporation may have voting and nonvoting stock. If a corporation meets the foregoing requirements and wishes to be taxed under Subchapter S, its shareholders may file Form 2553: "Election by a Small Business Corporation" with the Internal Revenue Service (IRS). The Form 2553 must be signed by all of the corporation's shareholders. If a shareholder resides in a community property state, the shareholder's spouse generally must also sign the 2553.