Did you know that most professional money
managers do not beat the broad market?
The majority of mutual fund managers
actually underperform their benchmarks in
the long and short term!
There are many reasons most investment
professionals and novices underperform
the market, the main one being human
nature. Successful investing requires a
lot of discipline. Investment decisions
should always be based on the most
important facts. Unfortunately, many
variables cloud an investor's mind during
the investment process. A few examples
include: second guessing trading
decisions, gut feelings and opinions in
the press.
The solution: mechanical investing
Stock Screening
Mechanical investing means allowing a
model to make investment decisions. This
may sound imprudent. After all, how can a
model know what is best? Actually, a
model will only be as smart as the
researcher who built it. The researcher
must design his investment model to
incorporate all pertinent variables that
should be considered in the investment
decision process. For example, if an
investor wants to build a stock screening
model, he should only include variables
in the model that have an impact on the
future direction of stock prices.
Determining which variables to include is
not an easy task. It requires a lot of
historical testing using a tool such as
the Zacks TSE software or Compustat. Such
tools allow researchers to test their
investment rules to see if they would
have been profitable in the past. For
example, if an investor wants to check if
low P/Es really matter, he can test a
rule based on P/Es, for instance to buy
all stocks when their P/E falls below 5
and sell them once their P/E rises above
10. Software such as Zacks TSE would
actually be able to test this rule vs.
every stock that has ever traded and
report how they performed while their
P/Es were between 5 and 10. Ideally, a
solid stock screening model would consist
of several rules that have all been
historically tested and that have proven
based on history that they have helped
screen for top performing stocks.
The Benefits
Creating a mechanical stock screening
model is definitely a lot of work.
However, it is well worth the effort, as
there are multiple benefits. It allows
investors to apply the identical stock
selection process, time after time, that
focuses only on the most important
variables, every time they are about to
buy or sell a stock. This is discipline
at its best! On top of that, once the
stock screen model has been designed
(i.e. all the variables have been
chosen), by using an inexpensive stock
screening software or free tools on the
internet (such as MSN's Stock Screener),
the investor can determine which stocks
meet the criteria with a single click.
This is far more efficient than digesting
every piece of available information. Not
to mention that most stock screeners can
analyze thousands of stocks in seconds.
It would be difficult for even a large
team of researchers to accomplish the
same task in weeks.
Conclusion
Most investors including professionals
prefer to actively manage their
portfolios and to really know their
stocks rather than use models. The
question to be asked is if this process
was so good, why do most investors
underperform the market?
Stock screening works because it forces
investors to buy and sell stocks without
emotion and with discipline, always
focusing on the factors that matter using
the exact same selection process every
single time.
Happy trading.