Stocks are a way of investing in a company to help it grow. Many people can gain and lose money from stocks. Shares are parts of companies stocks. Companies will sell shares of their business to make money. You can also sell your shares of the stock to make money. If you sell your shares while they cost less than what you bought it for, you will lose money. On the other hand, if you sell your shares when they cost more than what you bought it for, you gain money.