The investors are called stockholders and each part of stock they own is called a share . Investors try to pick companies that will perform well and be popular with other investors. The stock prices of these kinds of companies often will rise, creating a profit for shareholders. The more money an investor puts into a company, by buying more shares, the greater the possible rewards. The risks also are greater, since the performance of stocks is not guaranteed.
Stocks often go down, sometimes as quickly as they have gone up.
It's important to realize, however, that stockholders really do not make money or lose money until they sell their shares. Studying information about a company may help you decide whether or not to invest in a certain company. By looking at what products the company sells, how much of its profits come from each product and the accomplishments of the company you can determine if it is a good business in which to invest. Let's say you hear a tip that NIKE is coming out with a brand new product that is supposed to double its business. Its popularity is due largely to the use of NIKE shoes by famous athletes such as Chicago Bulls basketball star Michael Jordan.