| |
![]() September 2000 The Starting Point
OK, now that that's settled, what fundamental factors should you use? There's historical data like Return on Equity or last years earnings. There's forward-looking projections like future long-term growth rates. Then there's ratios like P/E and Price to Book. Which ones should you use? Obviously, you should use the ones that work best, the ones with the most As quants, we believe we can study what worked in the past to get a good idea of what will happen in the future. By finding what fundamental factors were correlated with previous price history, we hope to build a model that will help us select those stocks most likely to outperform in the future. The TheoryThe first step was to decide how performance would be measured. We settled on one year price percentage change. In other words, we wanted to find what fundamental factors were useful in predicting a stock's one year price percentage change.Next, we narrowed down the fundamental factors to those we felt were important. If we were wrong in what we chose, our statistical analysis would let us know. If we didn't include factors that were important, we could always go back and add them later. The initial eight factors were:
The ProcedureThe basis for our model is a stepwise multiple regression equation. (Don't worry, you don't have to do it.) Our eight fundamental factors are treated as independent variables and the 12-month percentage price change is the dependent variable. Our software starts with the assumption that all independent variables are meaningful and then tests the equation, removing any that aren't statistically significant.We ran this procedure in two different ways. First using all the stocks of the S&P 500 and then again for each sector independently. As expected, the results differed in each instance.
We then constructed two portfolios, one using the results from all 500 stocks (Portfolio 3), the other based on the top stocks from each sector (Portfolio 4). There was some overlap, but the sector based portfolio was much more balanced. This truly is a work in progress. The eight fundamental factors and the resulting portfolios are just a first pass. As time goes on, we'll adjust the factors and maybe even the regression process to sharpen the models' effectiveness. If you have any suggestions, we'd love to hear them. Portfolio 3The simplest way to use the data was to run the regression across the entire S&P 500. To do this, we let our software determine which factors were significant for all 500 stocks. This eliminated three: long-term debt/capital, P/E to growth, and long-term future growth rate. Having a value bent, we were a little gratified to see the growth-based factors eliminated.Next the software used the remaining factors to come up with the regression equation relating them to the expected 12-month percentage return of the 500 stocks. If you think back to high school algebra (as painful as that may be), you'll recall that this is simply an equation that sets the dependent variable (12-month percentage return) equal to a constant times each factor plus an intercept term. This allows you to simply fill in the values of the factors to calculate the expected 12-month percentage return for each stock in the index.
The resulting equation (shown above) has relatively strong explanatory power as evidenced by the the high R2. (If you're not statistically inclined, an explanation of the meaning of R2 is included in The Quantitative Approach.) The only thing that gave us some concern was the high correlation between two of the five independent factors, price to book and price to cash flow (.7966). We'll need to monitor this in the future, but for now we let it go and proceeded to apply the equation to the S&P 500.
We got our factor values from Baseline, plugged them in, and calculated expected return values for each stock. We then sorted the results from the highest to the lowest. Now we were ready to construct our portfolio. To do so, we simply took the top thirty stocks. Why thirty? No reason, other than it's a workable number to track and has the potential to provide enough diversification to eliminate non-systematic risk. Over 80% of the stocks in this portfolio were from the technology sector. In fact, only 5 of the S&P's 11 sectors were represented (see table,, above). This really shouldn't come as a surprise since the model is designed to pick stocks with the best 12 month performance potential. Very few would argue that consumer cyclicals or utilities will be great short-term performers. Going forward, we'll adjust this portfolio (P3) every other month around the 15th of the month. Stocks with rankings that have fallen below 40 will be removed and replaced with those not already in it with the highest rankings. Although there won't ever be more than 30 stocks in the portfolio, we'll let their rank fall below 40 before removing them to hold down turnover. Since P3 will be rebalanced six times a year, it should be more dynamic than P4. Portfolio 4Most folks would agree that different factors affect different sectors. In other words, a good predictor for one sector need not be effective for another.With this in mind, we went through the same procedure for each sector as we initially did for the entire S&P 500. As you would expect, we got different regression equations for each sector. The accompanying table shows which factors were significant for each as well as the coefficient values.
We constructed P4 by selecting the top-rated stocks in each sector. We didn't impose a limit on the number of stocks, but rather kept choosing until the sector weightings were roughly equivalent to those of the S&P 500 as of June 30, 2000. We ended up with 52 issues. (Current holdings in both P3 and P4 are available at these links.) This portfolio won't be as dynamic as P3. Since it's more sector neutral, we intend to let it run until next June without major modifications. Given we're attempting to determine its predictive power for one-year returns, it only makes sense to let it have a year before passing judgment. The only anticipated changes over the next twelve months will be additions or deletions due to mergers and acquisitions. ObservationsMost results went the way we thought they would yet there were still some surprises.It's logical to assume there would be differences in the factors affecting various sectors. This was borne out in P4. You'd also think the overall S&P would be affected differently than any individual sector. This was also confirmed given the differences in the two portfolios. P3's excessive technology weighting was also anticipated given that growth parameters were favored over value. Technology is where the growth has been and where the model predicts it will remain for the next 12 months. The sectors not represented in the portfolio have traditionally been slow-growth areas. But surprisingly, growth factors were not overly emphasized in P4, the sector model. The PEG ratio and earnings surprise -- two favorites of growth investors -- only fell in the middle of the pack. But then value factors such as return on capital, price to book, and forward P/E didn't do too well, either. The biggest surprise was the fact that plain old long-term future growth rate was the clear winner, appearing in 7 of the 11 sectors. No other factor came closer than 5. Does this mean growth is quantitatively more significant than value? Maybe it does, or maybe it just means growth has outperformed value over the past decade when the data for the models were compiled. Over the next several months, we'll get a better picture as we monitor and tweak the model. In the meantime, we'd like your help. What would you like to include or change in the model? Yes, you too can become part of this work in progress. E-mail your comments. *Source: Baseline Search this site! Just enter you key word or words:
Get current quotes or follow your own custom portfolio,
courtesy of E-Line Financials:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||