Sunday, May 20, 2007

Buffett on risk and diversification

Excerpt from Berkshire Hathaway’s 1993 Letter to Shareholders.

The strategy we’ve adopted precludes our following standard diversification dogma. Many pundits would therefore say the strategy must be riskier than that employed by more conventional investors. We disagree. We believe that a policy of portfolio concentration may well DECREASE risk if it raises, as it should, both the intensity with which an investor thinks about a business and the comfort-level he must feel with its economic characteristics before buying into it. In stating this opinion, we define risk, using dictionary terms, as “the possibility of loss or injury.”

Academics, however, like to define investment “risk” differently, averring that it is the relative volatility of a stock or portfolio of stocks – that is, their volatility as compared to that of a large universe of stocks. Employing data bases and statistical skills, these academics compute with precision the “beta” of a stock – its relative volatility in the past – and then build arcane investment and capital-allocation theories around this calculation. In their hunger for a single statistic to measure risk, however, they forget a fundamental principle: It is better to be approximately right than precisely wrong.

For owners of a business – and that’s the way we think of shareholders – the academics’ definition of risk is far off the mark, so much so that it produces absurdities. For example, under beta-based theory, a stock that has dropped very sharply compared to the market – as had Washington Post when we bought it in 1973 – becomes “riskier” at the lower price than it was at the higher price. Would that description have then made any sense to someone who was offered the entire company at a vastly-reduced price?

In fact, the true value investor WELCOMES volatility. Ben Graham explained why in Chapter 8 of THE INTELLIGENT INVESTOR. There he introduced “Mr. Market,” an obliging fellow who shows up every day to either buy from you or sell to you, whichever you wish. The more manic-depressive this chap is, the greater the opportunities available to the investor. That’s true because a wildly fluctuating market means that irrational low prices will periodically be attached to solid businesses. It is impossible to see how the availability of such prices can be though of as increasing the hazards for an investor who is totally free to either ignore the market or exploit its folly.

In assessing risk, a beta purist will disdain examining what a company produces, what its competitors are doing, or how much borrowed money the business employs. He may even prefer not to know the company’s name. What he treasures is the price history of its stock. In contrast, we’ll happily forgo knowing the price history and instead will seek whatever information will further our understanding of the company’s business. After we buy a stock, consequently, we would not be disturbed if markets closed for a year or two. We don’t need a daily quote on our 100% position in See’s or H.H. Brown to validate our well-being. Why, then, should we need a quote on our 7% (8.5% at end 2006, the amazing thing is BH did not even need to buy a single share since 1988 to increase their interest to 8.5%, and it’ll be interesting for you to think why it is so) interest in Coke?

In our opinion, the real risk an investor must assess is whether his aggregate after-tax receipts from an investment (including those he receives on sale) will, over his prospective holding period, give him at least as much purchasing power as he had to begin with, plus a modest rate of interest on that initial stake. Though this risk cannot be calculated with engineering precision, it can in some cases be judged with a degree of accuracy that is useful. The primary factors bearing upon this evaluation are:

1) The certainty with which the long-term economic characteristics of the business can be evaluated;
2) The certainty with which management can be evaluated, both as to its ability to realize the full potential of the business and to wisely employ its cash flows;
3) The certainty with which management can be counted on to channel the reward from the business to the shareholders rather than to himself;
4) The purchase price of the business;
5) The levels of taxation and inflation that will be experienced and that will determine the degree by which an investor’s purchasing-power return is reduced from his gross return.

These factors will probably strike many analysts as unbearably fuzzy since they cannot be extracted from a data base of any kind. But the difficulty of precisely quantifying these matters does not negate their importance nor is it insuperable. Just as Justice Steward found it impossible to formulate a test for obscenity but nevertheless asserted, “I know it when I see it,” so also can investors – in an inexact but useful way – “see” the risks inherent in certain investments without reference to complex equations or price histories.

Is it really so difficult to conclude that Coca-Cola and Gillette possess far less business risk over the long term than, say, any computer company or retailer? Worldwide, Coke sells about 44% of all soft drinks, and Gillette has more than 60% share (in value) of the blade market. Leaving aside chewing gum, in which Wrigley is dominant, I know of no other significant businesses in which the leading company has long enjoyed such global power.

Moreover, both Coke and Gillette have actually increased their worldwide shares of market in recent years. The might of their brand names, the attributes of their products, and the strength of their distribution systems give them an enormous competitive advantage, setting up a protective moat around their economic castles. The average company, in contrast, does battle without any such means of protection. As Peter Lynch says, stocks of companies selling commodity-like products should come with a warning label: “Competition may prove hazardous to human wealth.”

The competitive strengths of a Coke or Gillette are obvious to even the casual observer of business. Yet the beta of their stocks is similar to that of a great many run-of-the-mill companies who possess little or no competitive advantage. Should we conclude from this similarity that the competitive strength of Coke and Gillette gains them nothing when business risk is being measured? Or should we conclude that the risk in owning a piece of a company – its stock – is somehow divorced from the long-term risk inherent in its business operations? We believe neither conclusion makes sense and that equating beta with investment risk makes no sense.

The theoretician bred on beta has no mechanism for differentiating the risk inherent in, say, a single-product toy company selling pet rocks or hula hoops from that of another toy company whose sole product is Monopoly or Barbie. But it’s quite possible for ordinary investors to make such distinctions if they have a reasonable understanding of consumer behavior and the factors that create long-term competitive strength or weakness. Obviously, every investor will make mistakes. But by confining himself to a relatively few, easy-to-understand cases, a reasonably intelligent, informed and diligent person can judge investment risks with a useful degree of accuracy.

In many industries, of course, Charlie and I can’t determine whether we are dealing with a “pet rock” or a “Barbie.” We couldn’t solve this problem, moreover, even if we were to spend years intensely studying those industries. Sometimes our own intellectual shortcomings would stand in the way of understanding, and in other cases the nature of the industry would be the roadblock. For example, a business that must deal with fast-moving technology is not going to lend itself to reliable evaluations of its long-term economics. Did we foresee thirty years ago what would transpire in the television-manufacturing or computer industries? Of course not. (Nor did most of the investors and corporate managers who enthusiastically entered those industries.) Why, then, should Charlie and I now think we can predict the future of other rapidly-evolving businesses? We’ll stick instead with easy cases. Why search for a needle buried in a haystack when one is sitting in plain sight?

Of course, some investment strategies – for instance, our efforts in arbitrage over the years – require wide diversification. If significant risk exists in a single transaction, overall risk should be reduced by making that purchase one of many mutually-independent commitments. Thus, you may consciously purchase a risky investment – one that indeed has a significant possibility of causing loss or injury – if you believe that your gain, weighted for possibilities, considerably exceeds your loss, comparably weighted, and if you can commit to a number of similar, but unrelated opportunities. Most venture capitalists employ this strategy. Should you choose to pursue this course, you should adopt the outlook of a casino that owns a roulette wheel, which will want to see lots of action because it is favored by probabilities, but will refuse to accept a single, huge bet.

Another situation requiring wide diversification occurs when an investor who does not understand the economics of specific businesses nevertheless believes it in his interest to be a long-term investor of American industry. That investor should both own a large number of equities and space out his purchases. By periodically investing in an index fund, for example, the know-nothing investor can actually out-perform most investment professionals. Paradoxically, when “dumb” money acknowledges its limitation, it ceases to be “dumb.”

On the other hand, if you are a know-something investor, able to understand business economics and to find five to ten sensibly-priced companies that possess important long-term competitive advantages, conventional diversification makes no sense for you. It is apt simply to hurt your results and increase your risk. I cannot understand why an investor of that sort elects to put money into a business that is his 20th favorite rather than simply adding that money to his top choices – the businesses he understands best and that present the least risk, along with the greatest profit potential. In other words of the prophet Mae West: “Too much of a good thing can be wonderful.”

3 comments:

Rodrigo said...

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8percentpa said...

hmmm how did you get a spanish??? comment here?

Berkshire said...

Haha, I've absolutely no idea how a spanish audience get to my blog, neither do I understand him.