One of the most common investments is stocks. Owning a share of stock represents ownership in a company, specifically a corporation. Theoretically, the total value of that company is represented by the number of stock shares outstanding multiplied by the current price of one share of that stock. If it is a public company, the shares are traded on a public exchange such as the New York Stock Exchange or the NASDAQ.
Given that these shares are traded on these exchanges every business day, there is natural fluctuation in their value, even if there have been no significant changes in the status of the corporation that day. Supply and demand, not necessarily the intrinsic value of the corporation, determines the price of a stock at any given moment. As a result, there may be opportunities to buy or sell when the market overreacts, as it typically does. Given that there are literally thousands of corporations whose shares are traded publicly, there are a lot of stocks to choose from—hence the demand for professional management.