Like many investors right now, I’m spending a lot of time trying to figure out whether the stock market has actually hit a stable ‘bottom’ or whether it still has further to fall. My dad and I had a long discussion last night about different methodologies for calculating what \u00a0equity prices *should* be based on historical market behavior and the dynamics of the current situation. The two main factors that have driven the slide from the heights of October 2007 (DJIA @ 14,279.96 and S&P 500 @ 1,576.09) are the sudden de-leveraging of the financial markets (i.e. some major investors being forced to liquidate >75% of their positions) and the macroeconomic effects of a recessionary cycle (i.e. higher unemployment, lower consumer spending, deflation).<\/p>\n

While theoretically possible, I believe modeling the impact of these two factors is a practical impossibility because they are so intertwined — de-leveraging sparked the recession and the recession is driving further de-leveraging. You could also do a technical analysis where you try to match current market behavior to past patterns and extrapolate what happens next based on what happened before. But that method requires making a bet on which past patterns to match against, i.e. is our current situation more similar to the Great Depression or all the recessions since. And that’s a big bet.<\/p>\n

So, I propose a different (and much simpler) approach: assume a realistically sustainable growth rate over a long enough period and figure out where we would be if the market had grown at that pace. I picked 20 years as the period and charted the monthly percent change of the Dow Jones Industrial Average (DJIA) from 2,342.32 at the end of January 1989 to 8,131.33 at Friday’s close. The actual percent change is the blue<\/span> line, and I plotted 3 other lines against it: 10% annualized growth in green<\/span>; 6% annualized growth in orange<\/span>; and 2% annualized growth in red<\/span>.<\/p>\n