The single greatest mistake investors make is to extrapolate recent history out into the future. They take the financial returns of the past 5 days or 5 years or even 50 years and assume the next few days or years will look just the same without any consideration for the historical context or conditions that provided for those returns.
They forget that, while ‘history may rhyme, it doesn’t repeat itself’ (Twain). Or that, “the only thing that is constant is change” (Heraclitus). These two famous quotes apply to the financial markets as much as anything.
Ignoring these truths and instead simply extrapolating is why investors are suckered into pouring money into the stock market only after a run of great performance. They believe that the recent gains are about to repeat to their great benefit when they should be thinking about what conditions allowed for those gains to take place and analyzing whether they are still relevant or not.
This is also why they are suckered into selling only after a painful decline as they did at the lows made during the financial crisis. They believe that they are about to suffer another 50% decline on top of the one they just endured when they should really be reminding themselves that change is the only guarantee in life.
I believe this is one of the biggest problems with so-called “passive” investing. It is built upon the faulty premise that it is ‘impossible to forecast’ the future returns of any asset class over any period of time so we should just own all of them all the time. My response to this is that while ‘ignorance may be bliss’ it’s not a valid investment strategy.
In his 1992 letter to Berkshire Hathaway shareholders, Warren Buffett wrote:
We’ve long felt that the only value of stock forecasters is to make fortune tellers look good. Even now, Charlie and I continue to believe that short-term market forecasts are poison and should be kept locked up in a safe place, away from children and also from grown-ups who behave in the market like children. However, it is clear that stocks cannot forever overperform their underlying businesses, as they have so dramatically done for some time, and that fact makes us quite confident of our forecast that the rewards from investing in stocks over the next decade will be significantly smaller than they were in the last.
Much can be learned from this short passage. First, short-term stock market forecasts are, indeed, nearly worthless – essentially a guessing game. Second, long-term forecasts, on the other hand, can be made with ‘confidence.’ “How?” you ask.
It’s actually very simple. Rather than fixate on recent history and extrapolate it into the future you must abandon this natural tendency. And as I said earlier you also need to analyze the conditions that allowed for those returns to see whether they are still relevant to today’s market.
Source : The Felder report