The stock "IS" the company. Whoever owns a share of stock is part owner of a company. When the company earns money, it belongs to the owners (shareholders).
The present owners of the company have no reason to give away their money making business.
If you would like to be part owner of Yahoo!, you can go to a broker such as Scottrade or TD Ameritrade and buy some shares.
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Companies don't give shares to their customers (usually). Why would they?
