Don't borrow money to use for stock market investment. On the stock exchange, borrowed money is known as either gearing or leverage. It is typically used either by companies (to help them finance growth), investment banks and hedge funds (to help juice their returns) or very aggressive traders. There are many spread betting (information here), options trading and day trading strategies that use borrowed money to enhance returns, but it also has a very profound impact on the risks being taken with each trade.
Imagine owning stocks in five different companies, each of which you expect to continually grow profits. Unfortunately, circumstances change. At the end of the year, you might have two companies (A & B) that have performed well so their stocks are up 25% each. The stock of two other companies (C & D) in a different industry are up 10% each, while the fifth company’s (E) assets were liquidated to pay off a massive lawsuit.
The stock market works like an auction, and buyers and sellers can be individuals, corporations, or governments. When there are more sellers than buyers, the price of a stock will go down. When there are more buyers than sellers, the price will go up. A company's performance doesn't directly influence its stock price; it's investors' reaction to the performance that decides how the stock fluctuates. If a company is performing well, more people will want to own the stock—consequently driving the price up. The opposite is true when a company underperforms.
To make comparisons between companies, sectors and markets a little easier, there are a number of mathematical models used. The most common and often the most helpful is the P/E ratio. The Price to Earnings ratio takes the share price and is divided by the earnings per share. It is possible to calculate this using past earnings, projected future earnings and with all sorts of moving averages ;-) Therefore, this is one number that it is vital for any investor to know and understand.
Dollar-cost average: This sounds complicated, but it’s not. Dollar-cost averaging means investing a set amount of money at regular intervals, such as once per week or month. That set amount buys more shares when the stock price goes down and fewer shares when it rises, but overall, it evens out the average price you pay. Some online brokerage firms let investors set up an automated investing schedule.