Stocks, also known as equities, are shares of publicly listed companies in the stock exchange. When you buy a company’s share of stock, you become a shareholder of the company. Your equity interests in the company are determined by the number of shares you own in proportion to the number of outstanding shares. For example, if a company has 1,000 shares of stock outstanding and you own 100 shares, you will have a claim to 10% of the company's profits.