Common Stocks – When you invest in stock, you acquire an ownership stake in an actual operating business, along with your share of the net earnings and resulting dividends produced by the firm. Although you don't have to invest in stock to get rich, over the past could of centuries, equities (stocks) have been the highest returning asset class and have produced the most wealth. To learn more, read What Is Stock? which will break down the fundamentals.
When you've been approved for margin stock trading, you're also eligible to short stock. Almost every successful stock trader has shorted stock at one time or another. When you short stock, you make money when the company's shares fall—or, even better yet, when they crash. The problem is that you can expose yourself to unlimited liability when you do this.