No, when you buy stock you are buying part ownership of a company, if you already own the company there would be no reason to buy stock, for you will not be making or losing any money. It is also illegal, you are no supposed to have inside information about stocks when you buy them.
The public company enterprises work with the main motive of providing service to public. A public company is a company who offers stock to the general public. Anyone can buy a share or multiple shares of stock at that point owning part of that company.