Get a Widget for this title
RSS FeedPortfolio diversification: Positive or negative?
Results so far:
| Negative | 15% | 34 votes | Total: 223 votes | |
| Positive | 85% | 189 votes |
Negative
Write now
Print
Invite a writer™
Add to FavoritesSimply put, diversification is for the "investor" who knows not what he/she is doing. What is the popular phrase you always hear financial advisors or well-intentioned "seasoned" stock brokers say when they promote the virtues of diversification? "Diversification reduces risk!" they say. But how true is that statement?
Whether that statement is true or not depends on the correlation between the stocks in a particular portfolio - Having many stocks that are not correlated to each other reduces risk whereas having numerous stocks that are highly correlated to each other does not reduce risk at all. In fact, the latter increases your exposure to a particular sector. Let me illustrate with the following example. For simplicity's sake, let us assume you have a portfolio universe of only 2 stocks and the 1st stock being Exxon Mobil, an oil-related stock. If the second stock added to this portfolio is Chevron (another oil-related stock), both will move in tandem with current oil prices, and both will experience a downward price exposure should oil prices drop. In this case, diversification into Chevron stock increases your risk.
On the other hand, if the second stock added to this portfolio is an airline industry stock such as British Airways, your risk exposure actually decreases. Why is that so? This is because the British Airways stock will move in opposite direction with oil prices (Oil price increase leads to increase costs to fly airplanes which eats into the profits of the airlines.) Thus, in the event that oil prices drop, Exxon Mobil stock's price decrease will be counteracted by British Airways stock price increase.
However, it is important to note that even if one fills up his/her entire portfolio with stocks that have zero-correlation to each other, one cannot totally eliminate risk. This is because there is a non-diversifiable systematic risk known as the Beta coefficient. To avoid going into the technicalities of the Beta coefficient, I shall simply define it as type of risk that cannot be reduced through the effects of diversification.
Now that we understand that diversification may not reduce risks and that it will definitely not eliminate risks altogether, what is another drawback of diversification? This is the other side of the coin (to Risk) - And that is the Returns of the investment or portfolio. Diversification reduces the Returns of a portfolio.
To illustrate this point, let me compare the portfolio returns of a Diversified Investor versus that of a Focus Investor (defined as one who puts ALL his eggs into one singular basket). Let's assume both have $10,000 to invest with. The Diversified Investor will put $5,000 into Exxon Mobil and the remaining $5,000 into British Airways whereas the Focus Investor will put all $10,000 into Exxon Mobil. When oil prices rises, lets assume oil-related stocks will rise 10% and airline-related stocks will fall 10%. For the Diversified Investor, his gains and losses will cancel each other out and he will have zero returns (which corresponds with zero risks). For the Focus Investor, his portfolio return will be a positive $1,000 (10% of $10,000, ignoring transaction costs). On the contrary should oil prices fall, the Diversified Investor will again enjoy zero profits but the Focus Investor will lose $1,000 (Hence the concept of High Risks; High Rewards)
In conclusion, the reason for my statement "Diversification is for the "investor" who knows not what he/she is doing" is that for the Focus Investor who has done the necessary research and thoroughly understands the companies he/she is buying into, he/she will reasonably put his/her money into the few companies that he/she believes will outperform the market, in order to maximize the returns. The Focus Investor believes that diversification will actually dilute his potential returns. On the other hand, for the Diversified Investor who has no confidence in his/her purchases, he/she will naturally wants to cast his/her net as far out as possible, hoping that at least one stock will bring in the profits or that the profits of a few stocks will help to offset the losses of the rest. The Diversified Investor is more concerned with containing the risk exposure rather than maximizing his/her profits.
Diversificat ion and the Focus Investment strategy are contrary schools of thought Which strategy have you been practicing? Which strategy is more suitable for you? These are questions the individual will have to answer one's own.
Learn more about this author, aC.
Click here to send this author comments or questions.
Positive
PORTFOLIO DIVERSIFICATION: POSITIVE!
It is the objective of every rational stocks market investor to maximize return and minimize risk. This article deals with the minimization of that risk by simple random diversification of an equity portfolio and talks about why you should diversify.
THE RISK OF HOLDING SECURITIES
Portfolio theory talks about two types of risk: Market Risk and Unsystematic Risk.
Market risk can be caused by political, social or economic factors. Under this heading come: Interest Rate Risk, which is the uncertainty of future markets and income due to fluctuations in the general level of interest rates; and Purchasing Power Risk, which occurs as people lose their purchasing power due to inflation.
Unsystemat ic Risk is unique to a firm or industry. It may be Business Risk, which relates to things like the operational efficiency of a firm; or Finance Risk, which is dependent on the capital structure of the firm.
Based on the Market Model, the "Rs", being the return of a stock, can be divided into: "a", the alpha; "b", the beta; "Rm", the market return; and "e", the unexplained term or error. The equation is simply: Rs = a + (b * Rm) + e
The total variance or risk of holding this stock can be split into two parts: the variance of the (b*Rm) part of the equation; and the variance of the error term. The former is the market or systematic risk. The later is the residual variance or unsystematic risk.
RANDOM PORTFOLO DIVERSIFICATION
If you create a series of random portfolios of different sizes, say 2, 5, 10, 15 and 20 stock portfolios and then calculate their correlation with the S&P 500 index, you will find that the correlation rises as the portfolio size increases. Therefore the overall risk or deviation from the market return decreases with the number of stocks.
Furthermore if you calculate the residual variances for each of these portfolios you will find that the unsystematic risk falls quite rapidly at first, as the portfolio size increases, but then tails off. In fact the results of such an exercise are consistent with Fama's findings, which showed that it is unnecessary to purchase the whole market to diversify risk effectively. The rate of risk reduction is initially quite high, but flattens beyond 25-30 shares per portfolio.
TRADING AND DIVERSIFICATION
If you are trading it is important to diversify your portfolio as much as possible. It is true that the larger the portfolio, the harder it is to generate good ideas. Warren Buffett has emphasized this many times, but not everybody has a cash flow stream like he does, so it is all the more important for you to avoid panic selling of the holdings that you have and that you steer your portfolio like a large ship, which you should try to steer as calmly as possible though rough waters. Unrealized losses can always reverse back into profit, which means you have lost nothing. However, if you sell - you lose!
CONGLOMERATES AND COMPANY DIVERSIFICATION
There was a time that Conglomerates or Holding Companies were all the fashion. Eventually markets began to realize that the managers were not skilled in all the businesses they acquired, or in the countries they diversified into. They often had huge start-up costs with new ventures, or had to pay big premiums to do acquisitions from those in-the-know people, who were selling out. The tendency was more towards empire building than quality of earnings.
Buffett found his solution to this problem, by keeping on the management in the companies he bought. However, by simply buying shares of different companies in the market, you are diversifying earnings and keeping the management.
DIVERSIFI CATION AND BUFFETT
There are many myths about Warren Buffett. Few realize that he does trade in Derivatives, and is right now hedging his equity position using puts on the equity indices, despite his attacks on the dangers of their usage. Not many people know that Buffett is one of the most astute bond traders on the planet, or that he has successfully traded in the Silver Market, or that he takes huge currency positions. He was also one of the first people to invest in a Chinese Oil company and was involved in the rescue of Salomon Brothers, although it was not his typical style of investment. The point I wish to make here is that those who say that the great money is made by holding a small collection of assets that you understand is nonsense.
Buffett's investment success is not an argument against Diversification. Far from it! There is more to Buffett's success then just a few companies. It takes 50 years of investment experience to get to be a Buffett. You do not get experience by holding a few stocks. Buffett knows the workings of very many industries and markets. Buffett's success is also due in part to the country he was born in, the time he started investing and his early association with Benjamin Graham.
The other factor that is very important to note is that Buffett has used massive cash flows generated by insurance premiums from the Geico Corporation and his Reinsurance ventures to invest in equity markets during very long bull markets and times of unprecedented economic growth in the US economy. The average investor does not have the benefit of this infinite cash flow, which allows for perfect Dollar Cost Averaging. The typical investor has little money to invest in stocks when he is young, but can take more risk. Later in life he earns a lot more, but knows retirement is coming, so he is more risk averse. These factors are not relevant to Berkshire Hathaway, but they are to you and me and part of the solution is diversification.
CONC LUSION: PETER LYNCH
The last word is about Peter Lynch, who was made head of Fidelity's Magellan Fund in 1977. When he started the fund was worth $18 million. When he finished managing the fund in 1990, it was worth $14 billion. The punch line is that Peter Lynch had up to 1500 stocks in his portfolio and it most certainly did not hurt his performance.
Learn more about this author, Martin Chapman.
Click here to send this author comments or questions.
Difference of opinion? Debate now.
