One would think that there would be no difference between how Wall Street values a company and how it is done by the BV community, after excluding the valuation adjustments for privately-held status that business valuation consultants make. Analysts, money managers and traders on Wall Street and privately-held business valuation analysts get the same degrees, whether it is a bachelor's degree in accounting, economics or finance, or an MBA from a leading business school. Many on Wall Street and in the BV community possess the CFA credential. So if we are all learning the same techniques, why does it seem we have differing philosophies on value?
To make it clear what I mean, start off with a standard Wall Street analyst's report where Widget Corporation's stock is valued at $20, but is currently trading at $15. The release of the report is new information, so one would expect the stock to move toward $20 if Wall Street agrees with the analyst's opinion. Often, however, it seems like Wall Street focuses less on the overall valuation conclusion, and more on beating the EPS estimates for next year and next quarter. If Widget exceeds its quarterly earnings estimate by 10%, the stock may rise dramatically, sometimes 20% or more in the following month. More extreme are the consequences of an earnings miss, where a stock often drops 40% in a day on a 10% earnings miss. The overall result is to generate dramatic swings in market value on relatively small changes in quarterly performance.
So why is this occurring? Maybe we have to step back from the world of analysts and move into the world of Wall Street traders and mutual fund managers. Mutual funds are ranked quarterly and annually on their performance versus similar funds. These rankings are critical to the new money a fund can attract, and since a money manager usually gets paid based on his annual performance and assets under management, it has a direct impact on his bottom line. So the money manager is incentivized to focus on the short-term: stocks that are expected to rise in less than one year. Thus we read of fund managers doing "sector rotation" into stocks in sectors expected to perform well in the next few months. From this arises the old saying that "Wall Street anticipates earning six months into the future." This is even more extreme with stock traders, who are buying into a stock for a short-term price increase. Just read any stock board and you will see discussions that a stock is "dead money" (i.e. that it is not going to move in the near future). These stocks are dumped by traders.
In contrast, the business valuation professional considers the earnings history of a company for multiple years; many BV books recommend 5 years or more. He considers both past and future earnings performance. The BV analyst tries to determine if the past trend is sustainable or not, and relates this to the overall economy and industry at that time. Each past year's performance is a potential scenario of future earnings, so if we know that 2009 was a recessionary year and 2006 was a boom year, the analyst can see how external economic conditions affected the company's performance. Thus any forecast the company makes can be evaluated against past results and future economic expectations.
The academic literature on financial bubbles emphasizes that bubbles are often created when stock traders stray from valuation fundamentals and move toward a game of anticipating short-term increases. Traders may believe that stocks are overvalued, but still believe in the short-term that stock will become even more overvalued. Of course to make money this way, you have to be a believer in the "greater fool" theory, namely that after the stock rises, there will be a "greater fool" who will buy it from you at that price. Alan Greenspan referred to this as "irrational exuberance".
Yale Professor Robert Schiller borrowed Greenspan's phrase for the title of his book. In Irrational Exuberance, Schiller makes the case that in determining value we should take a long-term perspective. This puts Schiller in accordance with most BV practitioners in most cases. But Schiller's view of the long-term is long-term indeed.
Schiller's model to determine whether the market is overvalued is fairly simple. He uses a Price /Earnings ("P/E") ratio model where price is defined as the real (inflation adjusted) value of the S&P 500 index and earnings are defined as the average of the past TEN years of real (inflation adjusted) S&P 500 index earnings. Using this model, one can go back over the last 150+ years of stock market data and detect that stocks were clearly very overvalued in 1901, 1929, 1966 and 2000, and very undervalued in the early 1980s. (He uses a similar model to compare house prices to personal income, and one look makes it clear that the current housing crash was perfectly foreseeable).
So it looks like the valuation methodologies employed by BV analysts are more likely to avoid "irrational exuberance" than those used by Wall Street traders. It also reinforces the argument used by Ibbotson SBBI that the longer the data series, the more likely we are to avoid "irrational exuberance" or "irrational pessimism" in the calculation of equity risk premiums.