
My friend Phil called me last week. He wanted to know market conditions, as he was thinking of getting back into the market. Phil tries to time the market. That is, he gets out when he thinks the market is near a top and he gets back in when he thinks the market is near a bottom and has started back up. Is this a good strategy?
While I don't have Phil's investment results, I am pretty sure they would turn out to be below some acceptable index. Let me use a study I did to illustrate.
After Phil called, I wondered how many days the market moved up more than 3%. It turned out to be easy to get the data, so I looked at 5% and 10% one day moves as well. I looked at every trading day since January 3, 1928, a total of 19,691 trading days to January 5, 2006 for the S&P500 index. Here's what I found.
Days with positive moves greater than 3% = 231
Days with positive moves greater than 5% = 55
Days with positive moves greater than 10% = 6
Days with negative moves larger than 3% = 272
Days with negative moves larger than 5% = 62
Days with negative moves larger than 10%= 3 You can see the large up moves and large down moves are roughly the same size. So what does this mean for my friend Phil?
Let's say he was in the market and had one of the 3% down moves. This led him to sell his positions and move to the sidelines. He has locked in a 3% loss on his 401(k). While he is on the sidelines, the market moves up 3%. He decides to wait for a confirming move. He misses another up day. Then he buys back into the market. By his action, he has sold lower than the top and bought higher than the bottom, just the opposite of what you want to do, buy low and sell high. Those who held the index are ahead of him in returns.
Given the fact that we tend to hold on to our losers too long and sell our winners too soon, market timing is generally even worse than I am making it out to be. Even among the pros, there are very few market timing systems that show long term alpha (profit above the market return).
Poor Phil! (Pun intended)






Dollar cost averaging is a pretty good strategy for accumulating position.
When it comes to liquidating position, I find no fault in selling out to lock in a profit objective. You'll never go broke taking a profit. They don't ring any bells at the top of the market. Don't be afraid to leave a few points of additional appreciation on the table for the next guy (the one who takes you out at a profit).
When J.D. Rockafeller was asked by a reporter how it was that he had made all of his money in the stock market, he replied, "I sold too soon."
Posted by: Bob Hansell | February 11, 2006 8:50 PM | Permalink to Comment