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.
P/E ratio -- The price-to-earnings ratio is the most widely cited valuation metric, and for good reason. It's an easy way to compare similar businesses. Simply divide a company's current share price by its last 12 months' worth of earnings. You can also use the projected earnings over the next 12 months to calculate the forward P/E ratio. The key point to know is that P/E ratios are most useful when comparing businesses in the same industry -- such as comparing ExxonMobil (NYSE:XOM) and Chevron (NYSE:CVX).
In the professional world, one of the key concepts is diversification. Harry Markowitz is a Nobel prize winning economist and one of his major discoveries was that adding new asset classes can dramatically alter the overall risk profile of a portfolio. His finding was that a portfolio that contained very low risk assets would normally benefit from lower volatility and higher returns if a higher risk asset was added. This is due to the likely lack of correlation between high and low risk asset classes.
Since the underlying businesses operate in differing markets, sectors and countries, their quoted prices move independently as supply and demand in them rises and falls and new information is released to the public about the current business situation. It is the changing of prices that offer investors the opportunity to make a capital gain (or loss) via ownership.
Understand the risks associated with the stocks you are investing in. In the company’s 10-K, there is an extensive section that talks about the company’s risks. You also need to understand your own tolerance for risk. If you invest in a stock that is highly volatile and you are not comfortable with market fluctuation, owning the investment will make you anxious and more likely to sell when it does not make sense strategically.
The least demanding way to invest in the stock market is to invest through a fund. There are two types of funds. First is the actively managed mutual funds which have higher fees—92% of these funds fail to beat the underlying index over any three-year period. The second type is the index tracking fund, which typically has lower costs and is more effective in matching the growth of the stock market. This means they are growing in popularity because of the higher return on investment you receive. You should also use the most tax efficient way to invest: using your Investment Retirement Account (IRA) first. It’s best to invest in a low-cost, index-tracking fund through your tax-free IRA.
Use limit orders: Always use limit orders rather than market orders, when trading penny stocks. The very act of buying or selling shares in a company that is thinly traded can result in the price moving due to your trade. In other words, your buy might cause the shares to temporarily and artificially increase, then drop back down as soon as your purchase has been filled.