There are two types of classes of shares and these are Class A and Class B.

The two classes of shares determine what kind of voting rights do you have and that in turn determines what kind how much your opinion carries weight in the annual general meeting of the board.

Common stock is what we will discuss first and this stock of share is what is issued by the company in general and these shareholders who have the common stock then elect a board of directors which will make sure that the company has a good corporate policy. In terms of risk carrying the common stock carries maximum risk because once everyone is paid off only then can you as a common shareholder will be paid in the event of the liquidation of the company.

However most investors who invest in the stock market will like to take risk anyway because the risk has its own rewards as the common shares will typically appreciate in value if the company is doing well.

The preferred stock is less risky than the common stock and this kind of stock will generally be given preference over the common stock in the event of the firm going bankrupt. The preferred shareholders do get some amount of fixed didvidend.

For giving more voting power to certain type of shares the companies have Class A and Class B shares. Class A shares will have five or may be ten votes per share whereas Class B shares will only have one vote per share. This way there is more voting power for certain section of investors.

Try not be a casual investor and make sure to read the company prospectus as well as various bylaws.