Imagine that you own a business. If you were to divide that business up into small pieces and sell those pieces, you would essentially have issued stock. Quite simply, stock is ownership in a company. The money you raise from selling those "pieces" of your business can be used to build new plants and facilities, pay down debt, or acquire another company. A smart owner will keep at least 51% of the stock, which will allow them to retain control of the day to day activities. Any person or institution that owns over a majority of the stock is called the "controlling shareholder". Essentially, this person can do anything they want - right down to firing the CEO.
