Friday, October 31, 2008

Biased studies on market timing

On occasions we come across some articles that oppose the idea of market timing. To further their arguments, they show how longer term performance would get hampered if investors miss out on participating in 10/20/50 (or any other number) biggest up days in the markets. So, the studies claim that market timing is futile and not effective at all.

These studies seem to be one-sided and biased. They assume that market timers (like yours truly) will miss out on the up days while still stay exposed to all down days. Of course, with such an assumption, it can be 'proven' that market timing does not work and investors should refrain from making any attempt at timing the market.

Let us examine the truth based on hard data. Note that missing out on up days decreases your returns and avoiding down days increases your returns.

Let us examine the daily returns on the S&P CNX Nifty 50 since 1990.

If you had invested Rs. 100 in the Nifty on 3 July 1990, that would have grown to Rs. 966 as of 29th Oct 2008. This translates into an annual return of 13.2% compounded.

If you had missed out on the 10 biggest up days in the same Nifty, Rs 100 would have grown to Rs. 374 which translates into a compounded annual return of 7.5%. In contrast, if you had avoided the 10 worst days, Rs. 100 would have grown to Rs. 2661, which translates into a compounded annual return of 19.6%. So you would have given up on Rs. 592 (966-374 = 592) by missing the up days but gained Rs.1695 (2661-966 = 1695) by avoiding the down days.

If you had missed out on the 20 biggest up days in the same Nifty, Rs 100 would have grown to Rs. 192 which translates into a compounded annual return of 3.6%. In contrast, if you had avoided the 20 worst days, Rs. 100 would have grown to Rs. 5354, which translates into a compounded annual return of 24.2%. So you would have given up on Rs. 774 by missing the up days but gained Rs.4388 by avoiding the down days.

If you had missed out on the 50 biggest up days in the same Nifty, Rs 100 would have fallen to Rs. 40 which translates into a compounded annual return of (-4.9%). In contrast, if you had avoided the 50 worst days, Rs. 100 would have grown to a whopping Rs. 27678, which translates into a compounded annual return of 35.9%. So you would have given up on Rs. 926 by missing the up days but gained Rs. 26712 by avoiding the down days.

This data shows that successful attempts to avoid the worst down days would not only reduce risk (by decreasing the chance of a large decline) but gain much more than might be lost by missing some or even all of the biggest up days.


Moreover, there is no evidence in this that shows that trying to avoid the biggest down moves will result in missing the biggest up moves. Why should people think that market timers will be wrong all the time?

It is observed that most of the big up days up or down days occur in the midst of major trends. Such large trends are not too difficult to identify with simple market timing tools. These tools are not precise but are by and large effective. Market timers do not have to sell at the precise top or buy at the exact bottom. Market timers can exit in a downtrend identified ahead of major declines (like the current one). Such exits are likely to enhance returns very significantly. The same is true of entries. Market timers only need to identify that an uptrend is underway, and in most cases the big up days will follow.

Market participants, investors and speculators alike, should try to time the markets. This means 2 things:
1. Exit as quickly when a downtrend develops. This can be done via hedging a portfolio or selling out of positions. Once markets start going down, either sell out or use options/futures to protect your portfolio.
2. Enter the markets after an uptrend develops. Wait for the markets to tell you that an uptrend has developed and buy thereafter. This means not buying into a falling market even as stocks get cheaper and cheaper.

How to execute this is a different topic. However, in principle, this is one way of timing the markets and attempting to achieve superior returns.

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