In the broadest sense, stock breaks down into two classes: Common Stock and Preferred Stock. Common Stock. Common Stock is aptly named. It is the most common type of stock. Preferred Stock. When determining how to issue corporate stock, A, B, and F. Common Stock and Preferred Stock are A class is one group, or type, of stock shares all having identical rights; every share is the same as every other share. A corporation can issue two or more classes of stock shares. Class A - Class A shares are similar to the shares issued by a company with only one common stock class. That is, Class A shares are available to individual investors and publicly traded. Each share comes with one vote. Class B - Class B shares are similar to those described in the first example as Class A shares.