Investing would be easier if we weren’t always fighting against ourselves. We have natural tendencies that work against our own self-interest. We are not rational. We often make decisions based on emotion rather than based on a calculated cost-benefit analysis. (What follows is from The Psychology of Investing by John Nofsinger – required reading for the Level III CFA exam.)
First, we are overconfident in our abilities. For example, Garrison Keillor describes a fictitious place in Minnesota, Lake Wobegon, as a place where all the women are strong, all the men are good-looking, and all the children are above average. Additionally, when people describe their driving, they are invariably above average. Obviously, something has to give, not everyone can be above average. Not everyone can beat the markets, since everyone together is the market.
Overconfidence can lead to large investing mistakes. It can lead to large miscalculations in the amount of risk being taken. For example, the hedge fund Long Term Capital Management had the best and brightest designing it’s trading strategies (including two Nobel Laureates). But due to past successes, the partners developed an overconfidence that lead them to overleverage and pursue trades outside of their expertise. A couple warning signs that you are suffering from overconfidence is if you are trading too much or you are buying investments you don’t fully understand because you are either venturing into new territory or neglecting to do basic research.
Second, we tend to sell our “winners” too fast and hold our “losers” too long. The price at which a security is purchased should not affect the decision to sell. (The only exception is for tax purposes which is an incentive to sell losers and hold winners.) When you sell a loser, you admit to yourself that you failed, that you were wrong. When you sell a winner, you were right, and that feels good. Of course, the reason for buying or selling a security should be your estimate of the intrinsic value of the company and its shares.
Third, the past price movements of stocks affect the way we feel about stocks. If you bought a stock and made a lot of money, you are more likely to seek riskier investments since you are now playing with “house money.” So, if your investments in tech stocks went up the 90s you would be more likely to invest more of your money in risky tech ventures. If you recently lost money, you would be more likely to accept less risk. Often, the right move is the exact opposite: it’s better to be more aggressive after a market decline and less aggressive after a market advance.
Also, people want to at least break even. If you find yourself waiting to sell a stock because you want to break even, it is probably a good idea to sell. Or if you find yourself looking at past quotations or the original purchase price, try to keep that information out of your mind and redo an analysis of the company. What matters is not the return on any individual investment but the return on your whole portfolio. To that end you should track your long-term returns. That way, will be forced to face your real returns and won’t be fooled by the returns you remember. If your returns significantly trail the market over the long-run, it would be a good idea to either form a different investment strategy or, better yet, invest passively.
Fourth, we don’t account for things the right way. We create mental accounts for certain activities. For example, some people will maintain a large cash balance and credit card debt. It would be more economical to pay off the credit card debt and then use the credit cards in case of emergency. Another example is that people will not be averse to taking a large, risky mortgage but will never take out a margin loan or credit card loan – even if the margin loan or credit card loan is cheaper and less risky. The reason is we have a tendency to categorize and summarize rather than analyze.
Fifth, we are not able to look at a portfolio holistically. We are able to see the risk of individual investments but are not able to see how the individual investments fit into our portfolios. For example, equities are widely considered to be more risky than bonds. However, a portfolio of all bonds is probably riskier than a mix of stocks and bonds. This is because bonds and stocks often move in different directions. Instead of thinking of an individual security as risky or not, try to figure out how the risks associated with the investment fits into your overall portfolio.
Sixth, we often identify a good company as a good investment and a bad company as a bad investment. This is often not right. The real question is whether the value of the company is greater than the market value of the company. If the company is great, but everyone knows it is great, the price will reflect public knowledge and the shares may not be a good investment. For example, Google is a great company with great prospects but everyone already knows this and the stock is priced to reflect many years of uninterrupted growth. At its current price of $425.80, the stock is probably not undervalued. In fact, people often bid up the stock of great companies too much. This can be seen by noticing that stocks with low P/Es outperform high P/E stocks. Even though a company can be good, its stock is not necessarily good.
Seventh, we are much more likely to buy investments with which we are familiar. We are more likely to buy shares in local companies, especially our own company. We are also more likely to buy domestic rather than foreign companies. We do so because things that are familiar feel less risky. But concentrating our investments creates more risk. This is especially true when we invest in the stocks of the companies for which we work. Just ask anyone who worked for Enron, Global Crossing, Qwest, or any number of tech firms that shined and then fizzled. Buying stocks with which we are familiar gives us a warm, comfy feeling but can actually increase the risk we take.
When investing, we are our own biggest enemy. We are not built to make rational decisions but use mental shortcuts to arrive at decisions that are correct enough to serve us in the real world. But in the financial world our mental shortcuts can get us into serious trouble. We need to be aware of our psychological shortcomings so we can avoid making decisions based on psychological factors instead of real analysis.